Implement Animation Libraries

* Instead of containing single animations, AnimationPlayer now contains libraries.
* Libraries, in turn, contain the animations.

This paves the way for implementing the possibility of importing scenes as animation libraries, finally allowing to import animations separate from the 3D models.

Missing (will be done on separate PRs):

* Make it possible to import scenes (dae/fbx/gltf) as animation libraries.
* Make it possible for AnimationTree to import animation libraries on its own, so it does not rely on AnimationPlayer for everything.

21 files changed, 1739 insertions, 391 deletions

diff --git a/doc/classes/AnimationLibrary.xml b/doc/classes/AnimationLibrary.xml
new file mode 100644
index 0000000000..0a731edadd
--- /dev/null
+++ b/doc/classes/AnimationLibrary.xml
@@ -0,0 +1,70 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="AnimationLibrary" inherits="Resource" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+	<brief_description>
+	</brief_description>
+	<description>
+	</description>
+	<tutorials>
+	</tutorials>
+	<methods>
+		<method name="add_animation">
+			<return type="int" enum="Error" />
+			<argument index="0" name="name" type="StringName" />
+			<argument index="1" name="animation" type="Animation" />
+			<description>
+			</description>
+		</method>
+		<method name="get_animation" qualifiers="const">
+			<return type="Animation" />
+			<argument index="0" name="name" type="StringName" />
+			<description>
+			</description>
+		</method>
+		<method name="get_animation_list" qualifiers="const">
+			<return type="StringName[]" />
+			<description>
+			</description>
+		</method>
+		<method name="has_animation" qualifiers="const">
+			<return type="bool" />
+			<argument index="0" name="name" type="StringName" />
+			<description>
+			</description>
+		</method>
+		<method name="remove_animation">
+			<return type="void" />
+			<argument index="0" name="name" type="StringName" />
+			<description>
+			</description>
+		</method>
+		<method name="rename_animation">
+			<return type="void" />
+			<argument index="0" name="name" type="StringName" />
+			<argument index="1" name="newname" type="StringName" />
+			<description>
+			</description>
+		</method>
+	</methods>
+	<members>
+		<member name="_data" type="Dictionary" setter="_set_data" getter="_get_data" default="{}">
+		</member>
+	</members>
+	<signals>
+		<signal name="animation_added">
+			<argument index="0" name="name" type="Animation" />
+			<description>
+			</description>
+		</signal>
+		<signal name="animation_removed">
+			<argument index="0" name="name" type="Animation" />
+			<description>
+			</description>
+		</signal>
+		<signal name="animation_renamed">
+			<argument index="0" name="name" type="Animation" />
+			<argument index="1" name="to_name" type="Animation" />
+			<description>
+			</description>
+		</signal>
+	</signals>
+</class>
diff --git a/doc/classes/AnimationPlayer.xml b/doc/classes/AnimationPlayer.xml
index b1d04ce1f2..625cf3c47c 100644
--- a/doc/classes/AnimationPlayer.xml
+++ b/doc/classes/AnimationPlayer.xml
@@ -14,12 +14,11 @@
 		<link title="Third Person Shooter Demo">https://godotengine.org/asset-library/asset/678</link>
 	</tutorials>
 	<methods>
-		<method name="add_animation">
+		<method name="add_animation_library">
 			<return type="int" enum="Error" />
 			<argument index="0" name="name" type="StringName" />
-			<argument index="1" name="animation" type="Animation" />
+			<argument index="1" name="library" type="AnimationLibrary" />
 			<description>
-				Adds [code]animation[/code] to the player accessible with the key [code]name[/code].
 			</description>
 		</method>
 		<method name="advance">
@@ -63,6 +62,12 @@
 				Returns the name of [code]animation[/code] or an empty string if not found.
 			</description>
 		</method>
+		<method name="find_animation_library" qualifiers="const">
+			<return type="StringName" />
+			<argument index="0" name="animation" type="Animation" />
+			<description>
+			</description>
+		</method>
 		<method name="get_animation" qualifiers="const">
 			<return type="Animation" />
 			<argument index="0" name="name" type="StringName" />
@@ -70,6 +75,17 @@
 				Returns the [Animation] with key [code]name[/code] or [code]null[/code] if not found.
 			</description>
 		</method>
+		<method name="get_animation_library" qualifiers="const">
+			<return type="AnimationLibrary" />
+			<argument index="0" name="name" type="StringName" />
+			<description>
+			</description>
+		</method>
+		<method name="get_animation_library_list" qualifiers="const">
+			<return type="StringName[]" />
+			<description>
+			</description>
+		</method>
 		<method name="get_animation_list" qualifiers="const">
 			<return type="PackedStringArray" />
 			<description>
@@ -103,6 +119,12 @@
 				Returns [code]true[/code] if the [AnimationPlayer] stores an [Animation] with key [code]name[/code].
 			</description>
 		</method>
+		<method name="has_animation_library" qualifiers="const">
+			<return type="bool" />
+			<argument index="0" name="name" type="StringName" />
+			<description>
+			</description>
+		</method>
 		<method name="is_playing" qualifiers="const">
 			<return type="bool" />
 			<description>
@@ -138,19 +160,17 @@
 				[b]Note:[/b] If a looped animation is currently playing, the queued animation will never play unless the looped animation is stopped somehow.
 			</description>
 		</method>
-		<method name="remove_animation">
+		<method name="remove_animation_library">
 			<return type="void" />
 			<argument index="0" name="name" type="StringName" />
 			<description>
-				Removes the animation with key [code]name[/code].
 			</description>
 		</method>
-		<method name="rename_animation">
+		<method name="rename_animation_library">
 			<return type="void" />
 			<argument index="0" name="name" type="StringName" />
 			<argument index="1" name="newname" type="StringName" />
 			<description>
-				Renames an existing animation with key [code]name[/code] to [code]newname[/code].
 			</description>
 		</method>
 		<method name="seek">
diff --git a/doc/classes/OptionButton.xml b/doc/classes/OptionButton.xml
index 25e41116a2..b7145ab923 100644
--- a/doc/classes/OptionButton.xml
+++ b/doc/classes/OptionButton.xml
@@ -30,8 +30,9 @@
 		</method>
 		<method name="add_separator">
 			<return type="void" />
+			<argument index="0" name="text" type="String" default="&quot;&quot;" />
 			<description>
-				Adds a separator to the list of items. Separators help to group items. Separator also takes up an index and is appended at the end.
+				Adds a separator to the list of items. Separators help to group items, and can optionally be given a [code]text[/code] header. A separator also gets an index assigned, and is appended at the end of the item list.
 			</description>
 		</method>
 		<method name="clear">
@@ -89,6 +90,12 @@
 				[b]Warning:[/b] This is a required internal node, removing and freeing it may cause a crash. If you wish to hide it or any of its children, use their [member Window.visible] property.
 			</description>
 		</method>
+		<method name="get_selectable_item" qualifiers="const">
+			<return type="int" />
+			<argument index="0" name="from_last" type="bool" default="false" />
+			<description>
+			</description>
+		</method>
 		<method name="get_selected_id" qualifiers="const">
 			<return type="int" />
 			<description>
@@ -101,6 +108,11 @@
 				Gets the metadata of the selected item. Metadata for items can be set using [method set_item_metadata].
 			</description>
 		</method>
+		<method name="has_selectable_items" qualifiers="const">
+			<return type="bool" />
+			<description>
+			</description>
+		</method>
 		<method name="is_item_disabled" qualifiers="const">
 			<return type="bool" />
 			<argument index="0" name="idx" type="int" />
@@ -108,6 +120,12 @@
 				Returns [code]true[/code] if the item at index [code]idx[/code] is disabled.
 			</description>
 		</method>
+		<method name="is_item_separator" qualifiers="const">
+			<return type="bool" />
+			<argument index="0" name="idx" type="int" />
+			<description>
+			</description>
+		</method>
 		<method name="remove_item">
 			<return type="void" />
 			<argument index="0" name="idx" type="int" />
diff --git a/doc/classes/Tree.xml b/doc/classes/Tree.xml
index b8c39bee49..5abec4b437 100644
--- a/doc/classes/Tree.xml
+++ b/doc/classes/Tree.xml
@@ -179,8 +179,9 @@
 			<return type="Rect2" />
 			<argument index="0" name="item" type="TreeItem" />
 			<argument index="1" name="column" type="int" default="-1" />
+			<argument index="2" name="button_index" type="int" default="-1" />
 			<description>
-				Returns the rectangle area for the specified [TreeItem]. If [code]column[/code] is specified, only get the position and size of that column, otherwise get the rectangle containing all columns.
+				Returns the rectangle area for the specified [TreeItem]. If [code]column[/code] is specified, only get the position and size of that column, otherwise get the rectangle containing all columns. If a button index is specified, the rectangle of that button will be returned.
 			</description>
 		</method>
 		<method name="get_item_at_position" qualifiers="const">
diff --git a/editor/icons/AnimationLibrary.svg b/editor/icons/AnimationLibrary.svg
new file mode 100644
index 0000000000..0bac67d302
--- /dev/null
+++ b/editor/icons/AnimationLibrary.svg
@@ -0,0 +1 @@
+<svg height="16" width="16" xmlns="http://www.w3.org/2000/svg"><path d="M14.519 2.006A6 6 0 0 0 8.599 8a6 6 0 0 0 5.92 5.994v-1.01a1 1 0 0 1-.92-.984 1 1 0 0 1 .92-.984V4.984a1 1 0 0 1-.92-.984 1 1 0 0 1 .92-.984Zm-3.432 2.996a1 1 0 0 1 .547.133 1 1 0 0 1 .367 1.365 1 1 0 0 1-1.367.365A1 1 0 0 1 10.27 5.5a1 1 0 0 1 .818-.498ZM11.111 9a1 1 0 0 1 .89.5 1 1 0 0 1-.367 1.365 1 1 0 0 1-1.365-.365 1 1 0 0 1 .365-1.365A1 1 0 0 1 11.111 9Z" style="fill:#e0e0e0;fill-opacity:1"/><path d="M11.094 2.104a6 6 0 0 0-5.92 5.994 6 6 0 0 0 5.92 5.994v-.023a5.795 6.506 0 0 1-2.89-3.104 1 1 0 0 1-1.36-.367 1 1 0 0 1 .365-1.365 1 1 0 0 1 .475-.135 5.795 6.506 0 0 1-.076-.984 5.795 6.506 0 0 1 .082-1.027 1 1 0 0 1-.48-.124 1 1 0 0 1-.366-1.365 1 1 0 0 1 .818-.498 1 1 0 0 1 .547.133 1 1 0 0 1 .004.002 5.795 6.506 0 0 1 2.881-3.076z" style="fill:#e0e0e0;fill-opacity:1"/><path d="M7.616 2.104a6 6 0 0 0-5.92 5.994 6 6 0 0 0 5.92 5.994v-.023a5.795 6.506 0 0 1-2.89-3.104 1 1 0 0 1-1.36-.367 1 1 0 0 1 .366-1.365 1 1 0 0 1 .474-.135 5.795 6.506 0 0 1-.076-.984 5.795 6.506 0 0 1 .082-1.027 1 1 0 0 1-.48-.124 1 1 0 0 1-.366-1.365 1 1 0 0 1 .819-.498 1 1 0 0 1 .547.133 1 1 0 0 1 .003.002 5.795 6.506 0 0 1 2.881-3.076z" style="fill:#e0e0e0;fill-opacity:1"/></svg>
diff --git a/editor/import/editor_import_collada.cpp b/editor/import/editor_import_collada.cpp
index 69fa64c24c..97fc33ad25 100644
--- a/editor/import/editor_import_collada.cpp
+++ b/editor/import/editor_import_collada.cpp
@@ -1801,7 +1801,14 @@ Node *EditorSceneFormatImporterCollada::import_scene(const String &p_path, uint3
 				name = state.animations[i]->get_name();
 			}
 
-			ap->add_animation(name, state.animations[i]);
+			Ref<AnimationLibrary> library;
+			if (!ap->has_animation_library("")) {
+				library.instantiate();
+				ap->add_animation_library("", library);
+			} else {
+				library = ap->get_animation_library("");
+			}
+			library->add_animation(name, state.animations[i]);
 		}
 		state.scene->add_child(ap, true);
 		ap->set_owner(state.scene);
diff --git a/editor/import/resource_importer_scene.cpp b/editor/import/resource_importer_scene.cpp
index e7c605aaf0..19aceb6c80 100644
--- a/editor/import/resource_importer_scene.cpp
+++ b/editor/import/resource_importer_scene.cpp
@@ -473,7 +473,9 @@ Node *ResourceImporterScene::_pre_fix_node(Node *p_node, Node *p_root, Map<Ref<I
 				if (_teststr(animname, loop_strings[i])) {
 					anim->set_loop_mode(Animation::LoopMode::LOOP_LINEAR);
 					animname = _fixstr(animname, loop_strings[i]);
-					ap->rename_animation(E, animname);
+
+					Ref<AnimationLibrary> library = ap->get_animation_library(ap->find_animation_library(anim));
+					library->rename_animation(E, animname);
 				}
 			}
 		}
@@ -1019,7 +1021,8 @@ Node *ResourceImporterScene::_post_fix_node(Node *p_node, Node *p_root, Map<Ref<
 					Ref<Animation> saved_anim = _save_animation_to_file(anim, save, path, keep_custom);
 
 					if (saved_anim != anim) {
-						ap->add_animation(name, saved_anim); //replace
+						Ref<AnimationLibrary> al = ap->get_animation_library(ap->find_animation_library(anim));
+						al->add_animation(name, saved_anim); //replace
 					}
 				}
 			}
@@ -1109,6 +1112,7 @@ void ResourceImporterScene::_create_clips(AnimationPlayer *anim, const Array &p_
 	}
 
 	Ref<Animation> default_anim = anim->get_animation("default");
+	Ref<AnimationLibrary> al = anim->get_animation_library(anim->find_animation(default_anim));
 
 	for (int i = 0; i < p_clips.size(); i += 7) {
 		String name = p_clips[i];
@@ -1246,15 +1250,16 @@ void ResourceImporterScene::_create_clips(AnimationPlayer *anim, const Array &p_
 
 		new_anim->set_loop_mode(loop_mode);
 		new_anim->set_length(to - from);
-		anim->add_animation(name, new_anim);
+
+		al->add_animation(name, new_anim);
 
 		Ref<Animation> saved_anim = _save_animation_to_file(new_anim, save_to_file, save_to_path, keep_current);
 		if (saved_anim != new_anim) {
-			anim->add_animation(name, saved_anim);
+			al->add_animation(name, saved_anim);
 		}
 	}
 
-	anim->remove_animation("default"); //remove default (no longer needed)
+	al->remove_animation("default"); // Remove default (no longer needed).
 }
 
 void ResourceImporterScene::_optimize_animations(AnimationPlayer *anim, float p_max_lin_error, float p_max_ang_error, float p_max_angle) {
diff --git a/editor/plugins/animation_library_editor.cpp b/editor/plugins/animation_library_editor.cpp
new file mode 100644
index 0000000000..2e9a82a7c2
--- /dev/null
+++ b/editor/plugins/animation_library_editor.cpp
@@ -0,0 +1,689 @@
+/*************************************************************************/
+/*  animation_library_editor.cpp                                         */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "animation_library_editor.h"
+#include "editor/editor_file_dialog.h"
+#include "editor/editor_node.h"
+#include "editor/editor_scale.h"
+
+void AnimationLibraryEditor::set_animation_player(Object *p_player) {
+	player = p_player;
+}
+
+void AnimationLibraryEditor::_add_library() {
+	add_library_dialog->set_title(TTR("Library Name:"));
+	add_library_name->set_text("");
+	add_library_dialog->popup_centered();
+	add_library_name->grab_focus();
+	adding_animation = false;
+	adding_animation_to_library = StringName();
+	_add_library_validate("");
+}
+
+void AnimationLibraryEditor::_add_library_validate(const String &p_name) {
+	String error;
+
+	if (adding_animation) {
+		Ref<AnimationLibrary> al = player->call("get_animation_library", adding_animation_to_library);
+		ERR_FAIL_COND(al.is_null());
+		if (p_name == "") {
+			error = TTR("Animation name can't be empty.");
+
+		} else if (String(p_name).contains("/") || String(p_name).contains(":") || String(p_name).contains(",") || String(p_name).contains("[")) {
+			error = TTR("Animation name contains invalid characters: '/', ':', ',' or '['.");
+		} else if (al->has_animation(p_name)) {
+			error = TTR("Animation with the same name already exists.");
+		}
+
+	} else {
+		if (p_name == "" && bool(player->call("has_animation_library", ""))) {
+			error = TTR("Enter a library name.");
+		} else if (String(p_name).contains("/") || String(p_name).contains(":") || String(p_name).contains(",") || String(p_name).contains("[")) {
+			error = TTR("Library name contains invalid characters: '/', ':', ',' or '['.");
+		} else if (bool(player->call("has_animation_library", p_name))) {
+			error = TTR("Library with the same name already exists.");
+		}
+	}
+
+	if (error != "") {
+		add_library_validate->add_theme_color_override("font_color", get_theme_color(SNAME("error_color"), SNAME("Editor")));
+		add_library_validate->set_text(error);
+		add_library_dialog->get_ok_button()->set_disabled(true);
+	} else {
+		add_library_validate->add_theme_color_override("font_color", get_theme_color(SNAME("success_color"), SNAME("Editor")));
+		if (p_name == "") {
+			add_library_validate->set_text(TTR("Global library will be created."));
+		} else {
+			add_library_validate->set_text(TTR("Library name is valid."));
+		}
+		add_library_dialog->get_ok_button()->set_disabled(false);
+	}
+}
+
+void AnimationLibraryEditor::_add_library_confirm() {
+	if (adding_animation) {
+		String anim_name = add_library_name->get_text();
+		UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+
+		Ref<AnimationLibrary> al = player->call("get_animation_library", adding_animation_to_library);
+		ERR_FAIL_COND(!al.is_valid());
+
+		Ref<Animation> anim;
+		anim.instantiate();
+
+		undo_redo->create_action(vformat(TTR("Add Animation to Library: %s"), anim_name));
+		undo_redo->add_do_method(al.ptr(), "add_animation", anim_name, anim);
+		undo_redo->add_undo_method(al.ptr(), "remove_animation", anim_name);
+		undo_redo->add_do_method(this, "_update_editor", player);
+		undo_redo->add_undo_method(this, "_update_editor", player);
+		undo_redo->commit_action();
+
+	} else {
+		String lib_name = add_library_name->get_text();
+		UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+
+		Ref<AnimationLibrary> al;
+		al.instantiate();
+
+		undo_redo->create_action(vformat(TTR("Add Animation Library: %s"), lib_name));
+		undo_redo->add_do_method(player, "add_animation_library", lib_name, al);
+		undo_redo->add_undo_method(player, "remove_animation_library", lib_name);
+		undo_redo->add_do_method(this, "_update_editor", player);
+		undo_redo->add_undo_method(this, "_update_editor", player);
+		undo_redo->commit_action();
+	}
+}
+
+void AnimationLibraryEditor::_load_library() {
+	List<String> extensions;
+	ResourceLoader::get_recognized_extensions_for_type("AnimationLibrary", &extensions);
+
+	file_dialog->set_title(TTR("Load Animation"));
+	file_dialog->clear_filters();
+	for (const String &K : extensions) {
+		file_dialog->add_filter("*." + K);
+	}
+
+	file_dialog->set_file_mode(EditorFileDialog::FILE_MODE_OPEN_FILE);
+	file_dialog->set_current_file("");
+	file_dialog->popup_centered_ratio();
+
+	file_dialog_action = FILE_DIALOG_ACTION_OPEN_LIBRARY;
+}
+
+void AnimationLibraryEditor::_file_popup_selected(int p_id) {
+	Ref<AnimationLibrary> al = player->call("get_animation_library", file_dialog_library);
+	Ref<Animation> anim;
+	if (file_dialog_animation != StringName()) {
+		anim = al->get_animation(file_dialog_animation);
+		ERR_FAIL_COND(anim.is_null());
+	}
+	switch (p_id) {
+		case FILE_MENU_SAVE_LIBRARY: {
+			if (al->get_path().is_resource_file()) {
+				EditorNode::get_singleton()->save_resource(al);
+				break;
+			}
+			[[fallthrough]];
+		}
+		case FILE_MENU_SAVE_AS_LIBRARY: {
+			file_dialog->set_file_mode(EditorFileDialog::FILE_MODE_SAVE_FILE);
+			file_dialog->set_title(TTR("Save Library"));
+			if (al->get_path().is_resource_file()) {
+				file_dialog->set_current_path(al->get_path());
+			} else {
+				file_dialog->set_current_file(String(file_dialog_library) + ".res");
+			}
+			file_dialog->clear_filters();
+			List<String> exts;
+			ResourceLoader::get_recognized_extensions_for_type("AnimationLibrary", &exts);
+			for (const String &K : exts) {
+				file_dialog->add_filter("*." + K);
+			}
+
+			file_dialog->popup_centered_ratio();
+			file_dialog_action = FILE_DIALOG_ACTION_SAVE_LIBRARY;
+		} break;
+		case FILE_MENU_MAKE_LIBRARY_UNIQUE: {
+			StringName lib_name = file_dialog_library;
+
+			Ref<AnimationLibrary> ald = al->duplicate();
+
+			UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+			undo_redo->create_action(vformat(TTR("Make Animation Library Unique: %s"), lib_name));
+			undo_redo->add_do_method(player, "remove_animation_library", lib_name);
+			undo_redo->add_do_method(player, "add_animation_library", lib_name, ald);
+			undo_redo->add_undo_method(player, "remove_animation_library", lib_name);
+			undo_redo->add_undo_method(player, "add_animation_library", lib_name, al);
+			undo_redo->add_do_method(this, "_update_editor", player);
+			undo_redo->add_undo_method(this, "_update_editor", player);
+			undo_redo->commit_action();
+
+		} break;
+		case FILE_MENU_EDIT_LIBRARY: {
+			EditorNode::get_singleton()->push_item(al.ptr());
+		} break;
+
+		case FILE_MENU_SAVE_ANIMATION: {
+			if (anim->get_path().is_resource_file()) {
+				EditorNode::get_singleton()->save_resource(anim);
+				break;
+			}
+			[[fallthrough]];
+		}
+		case FILE_MENU_SAVE_AS_ANIMATION: {
+			file_dialog->set_file_mode(EditorFileDialog::FILE_MODE_SAVE_FILE);
+			file_dialog->set_title(TTR("Save Animation"));
+			if (anim->get_path().is_resource_file()) {
+				file_dialog->set_current_path(anim->get_path());
+			} else {
+				file_dialog->set_current_file(String(file_dialog_animation) + ".res");
+			}
+			file_dialog->clear_filters();
+			List<String> exts;
+			ResourceLoader::get_recognized_extensions_for_type("Animation", &exts);
+			for (const String &K : exts) {
+				file_dialog->add_filter("*." + K);
+			}
+
+			file_dialog->popup_centered_ratio();
+			file_dialog_action = FILE_DIALOG_ACTION_SAVE_ANIMATION;
+		} break;
+		case FILE_MENU_MAKE_ANIMATION_UNIQUE: {
+			StringName anim_name = file_dialog_animation;
+
+			Ref<Animation> animd = anim->duplicate();
+
+			UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+			undo_redo->create_action(vformat(TTR("Make Animation Unique: %s"), anim_name));
+			undo_redo->add_do_method(al.ptr(), "remove_animation", anim_name);
+			undo_redo->add_do_method(al.ptr(), "add_animation", anim_name, animd);
+			undo_redo->add_undo_method(al.ptr(), "remove_animation", anim_name);
+			undo_redo->add_undo_method(al.ptr(), "add_animation", anim_name, anim);
+			undo_redo->add_do_method(this, "_update_editor", player);
+			undo_redo->add_undo_method(this, "_update_editor", player);
+			undo_redo->commit_action();
+		} break;
+		case FILE_MENU_EDIT_ANIMATION: {
+			EditorNode::get_singleton()->push_item(anim.ptr());
+		} break;
+	}
+}
+void AnimationLibraryEditor::_load_file(String p_path) {
+	switch (file_dialog_action) {
+		case FILE_DIALOG_ACTION_OPEN_LIBRARY: {
+			Ref<AnimationLibrary> al = ResourceLoader::load(p_path);
+			if (al.is_null()) {
+				error_dialog->set_text(TTR("Invalid AnimationLibrary file."));
+				error_dialog->popup_centered();
+				return;
+			}
+
+			TypedArray<StringName> libs = player->call("get_animation_library_list");
+			for (int i = 0; i < libs.size(); i++) {
+				const StringName K = libs[i];
+				Ref<AnimationLibrary> al2 = player->call("get_animation_library", K);
+				if (al2 == al) {
+					error_dialog->set_text(TTR("This library is already added to the player."));
+					error_dialog->popup_centered();
+
+					return;
+				}
+			}
+
+			String name = p_path.get_file().get_basename();
+
+			int attempt = 1;
+
+			while (bool(player->call("has_animation_library", name))) {
+				attempt++;
+				name = p_path.get_file().get_basename() + " " + itos(attempt);
+			}
+
+			UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+
+			undo_redo->create_action(vformat(TTR("Add Animation Library: %s"), name));
+			undo_redo->add_do_method(player, "add_animation_library", name, al);
+			undo_redo->add_undo_method(player, "remove_animation_library", name);
+			undo_redo->add_do_method(this, "_update_editor", player);
+			undo_redo->add_undo_method(this, "_update_editor", player);
+			undo_redo->commit_action();
+		} break;
+		case FILE_DIALOG_ACTION_OPEN_ANIMATION: {
+			Ref<Animation> anim = ResourceLoader::load(p_path);
+			if (anim.is_null()) {
+				error_dialog->set_text(TTR("Invalid Animation file."));
+				error_dialog->popup_centered();
+				return;
+			}
+
+			Ref<AnimationLibrary> al = player->call("get_animation_library", adding_animation_to_library);
+			List<StringName> anims;
+			al->get_animation_list(&anims);
+			for (const StringName &K : anims) {
+				Ref<Animation> a2 = al->get_animation(K);
+				if (a2 == anim) {
+					error_dialog->set_text(TTR("This animation is already added to the library."));
+					error_dialog->popup_centered();
+					return;
+				}
+			}
+
+			String name = p_path.get_file().get_basename();
+
+			int attempt = 1;
+
+			while (al->has_animation(name)) {
+				attempt++;
+				name = p_path.get_file().get_basename() + " " + itos(attempt);
+			}
+
+			UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+
+			undo_redo->create_action(vformat(TTR("Load Animation into Library: %s"), name));
+			undo_redo->add_do_method(al.ptr(), "add_animation", name, anim);
+			undo_redo->add_undo_method(al.ptr(), "remove_animation", name);
+			undo_redo->add_do_method(this, "_update_editor", player);
+			undo_redo->add_undo_method(this, "_update_editor", player);
+			undo_redo->commit_action();
+		} break;
+
+		case FILE_DIALOG_ACTION_SAVE_LIBRARY: {
+			Ref<AnimationLibrary> al = player->call("get_animation_library", file_dialog_library);
+			String prev_path = al->get_path();
+			EditorNode::get_singleton()->save_resource_in_path(al, p_path);
+
+			if (al->get_path() != prev_path) { // Save successful.
+				UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+
+				undo_redo->create_action(vformat(TTR("Save Animation library to File: %s"), file_dialog_library));
+				undo_redo->add_do_method(al.ptr(), "set_path", al->get_path());
+				undo_redo->add_undo_method(al.ptr(), "set_path", prev_path);
+				undo_redo->add_do_method(this, "_update_editor", player);
+				undo_redo->add_undo_method(this, "_update_editor", player);
+				undo_redo->commit_action();
+			}
+
+		} break;
+		case FILE_DIALOG_ACTION_SAVE_ANIMATION: {
+			Ref<AnimationLibrary> al = player->call("get_animation_library", file_dialog_library);
+			Ref<Animation> anim;
+			if (file_dialog_animation != StringName()) {
+				anim = al->get_animation(file_dialog_animation);
+				ERR_FAIL_COND(anim.is_null());
+			}
+			String prev_path = anim->get_path();
+			EditorNode::get_singleton()->save_resource_in_path(anim, p_path);
+			if (anim->get_path() != prev_path) { // Save successful.
+				UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+
+				undo_redo->create_action(vformat(TTR("Save Animation to File: %s"), file_dialog_animation));
+				undo_redo->add_do_method(anim.ptr(), "set_path", anim->get_path());
+				undo_redo->add_undo_method(anim.ptr(), "set_path", prev_path);
+				undo_redo->add_do_method(this, "_update_editor", player);
+				undo_redo->add_undo_method(this, "_update_editor", player);
+				undo_redo->commit_action();
+			}
+		} break;
+	}
+}
+
+void AnimationLibraryEditor::_item_renamed() {
+	TreeItem *ti = tree->get_edited();
+	String text = ti->get_text(0);
+	String old_text = ti->get_metadata(0);
+	bool restore_text = false;
+	UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+
+	if (String(text).contains("/") || String(text).contains(":") || String(text).contains(",") || String(text).contains("[")) {
+		restore_text = true;
+	} else {
+		if (ti->get_parent() == tree->get_root()) {
+			// Renamed library
+
+			if (player->call("has_animation_library", text)) {
+				restore_text = true;
+			} else {
+				undo_redo->create_action(vformat(TTR("Rename Animation Library: %s"), text));
+				undo_redo->add_do_method(player, "rename_animation_library", old_text, text);
+				undo_redo->add_undo_method(player, "rename_animation_library", text, old_text);
+				undo_redo->add_do_method(this, "_update_editor", player);
+				undo_redo->add_undo_method(this, "_update_editor", player);
+				updating = true;
+				undo_redo->commit_action();
+				updating = false;
+				ti->set_metadata(0, text);
+				if (text == "") {
+					ti->set_suffix(0, TTR("[Global]"));
+				} else {
+					ti->set_suffix(0, "");
+				}
+			}
+		} else {
+			// Renamed anim
+			StringName library = ti->get_parent()->get_metadata(0);
+			Ref<AnimationLibrary> al = player->call("get_animation_library", library);
+
+			if (al.is_valid()) {
+				if (al->has_animation(text)) {
+					restore_text = true;
+				} else {
+					undo_redo->create_action(vformat(TTR("Rename Animation: %s"), text));
+					undo_redo->add_do_method(al.ptr(), "rename_animation", old_text, text);
+					undo_redo->add_undo_method(al.ptr(), "rename_animation", text, old_text);
+					undo_redo->add_do_method(this, "_update_editor", player);
+					undo_redo->add_undo_method(this, "_update_editor", player);
+					updating = true;
+					undo_redo->commit_action();
+					updating = false;
+
+					ti->set_metadata(0, text);
+				}
+			} else {
+				restore_text = true;
+			}
+		}
+	}
+
+	if (restore_text) {
+		ti->set_text(0, old_text);
+	}
+}
+
+void AnimationLibraryEditor::_button_pressed(TreeItem *p_item, int p_column, int p_button) {
+	if (p_item->get_parent() == tree->get_root()) {
+		// Library
+		StringName lib_name = p_item->get_metadata(0);
+		Ref<AnimationLibrary> al = player->call("get_animation_library", lib_name);
+		switch (p_button) {
+			case LIB_BUTTON_ADD: {
+				add_library_dialog->set_title(TTR("Animation Name:"));
+				add_library_name->set_text("");
+				add_library_dialog->popup_centered();
+				add_library_name->grab_focus();
+				adding_animation = true;
+				adding_animation_to_library = p_item->get_metadata(0);
+				_add_library_validate("");
+			} break;
+			case LIB_BUTTON_LOAD: {
+				adding_animation_to_library = p_item->get_metadata(0);
+				List<String> extensions;
+				ResourceLoader::get_recognized_extensions_for_type("Animation", &extensions);
+
+				file_dialog->clear_filters();
+				for (const String &K : extensions) {
+					file_dialog->add_filter("*." + K);
+				}
+
+				file_dialog->set_title(TTR("Load Animation"));
+				file_dialog->set_file_mode(EditorFileDialog::FILE_MODE_OPEN_FILE);
+				file_dialog->set_current_file("");
+				file_dialog->popup_centered_ratio();
+
+				file_dialog_action = FILE_DIALOG_ACTION_OPEN_ANIMATION;
+
+			} break;
+			case LIB_BUTTON_PASTE: {
+				Ref<Animation> anim = EditorSettings::get_singleton()->get_resource_clipboard();
+				if (!anim.is_valid()) {
+					error_dialog->set_text(TTR("No animation resource in clipboard!"));
+					error_dialog->popup_centered();
+					return;
+				}
+
+				anim = anim->duplicate(); // Users simply dont care about referencing, so making a copy works better here.
+
+				String base_name;
+				if (anim->get_name() != "") {
+					base_name = anim->get_name();
+				} else {
+					base_name = TTR("Pasted Animation");
+				}
+
+				String name = base_name;
+				int attempt = 1;
+				while (al->has_animation(name)) {
+					attempt++;
+					name = base_name + " " + itos(attempt);
+				}
+
+				UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+
+				undo_redo->create_action(vformat(TTR("Add Animation to Library: %s"), name));
+				undo_redo->add_do_method(al.ptr(), "add_animation", name, anim);
+				undo_redo->add_undo_method(al.ptr(), "remove_animation", name);
+				undo_redo->add_do_method(this, "_update_editor", player);
+				undo_redo->add_undo_method(this, "_update_editor", player);
+				undo_redo->commit_action();
+
+			} break;
+			case LIB_BUTTON_FILE: {
+				file_popup->clear();
+				file_popup->add_item(TTR("Save"), FILE_MENU_SAVE_LIBRARY);
+				file_popup->add_item(TTR("Save As"), FILE_MENU_SAVE_AS_LIBRARY);
+				file_popup->add_separator();
+				file_popup->add_item(TTR("Make Unique"), FILE_MENU_MAKE_LIBRARY_UNIQUE);
+				file_popup->add_separator();
+				file_popup->add_item(TTR("Open in Inspector"), FILE_MENU_EDIT_LIBRARY);
+				Rect2 pos = tree->get_item_rect(p_item, 1, 0);
+				Vector2 popup_pos = tree->get_screen_position() + pos.position + Vector2(0, pos.size.height);
+				file_popup->popup(Rect2(popup_pos, Size2()));
+
+				file_dialog_animation = StringName();
+				file_dialog_library = lib_name;
+			} break;
+			case LIB_BUTTON_DELETE: {
+				UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+				undo_redo->create_action(vformat(TTR("Remove Animation Library: %s"), lib_name));
+				undo_redo->add_do_method(player, "remove_animation_library", lib_name);
+				undo_redo->add_undo_method(player, "add_animation_library", lib_name, al);
+				undo_redo->add_do_method(this, "_update_editor", player);
+				undo_redo->add_undo_method(this, "_update_editor", player);
+				undo_redo->commit_action();
+			} break;
+		}
+
+	} else {
+		// Animation
+		StringName lib_name = p_item->get_parent()->get_metadata(0);
+		StringName anim_name = p_item->get_metadata(0);
+		Ref<AnimationLibrary> al = player->call("get_animation_library", lib_name);
+		Ref<Animation> anim = al->get_animation(anim_name);
+		ERR_FAIL_COND(!anim.is_valid());
+		switch (p_button) {
+			case ANIM_BUTTON_COPY: {
+				if (anim->get_name() == "") {
+					anim->set_name(anim_name); // Keep the name around
+				}
+				EditorSettings::get_singleton()->set_resource_clipboard(anim);
+			} break;
+			case ANIM_BUTTON_FILE: {
+				file_popup->clear();
+				file_popup->add_item(TTR("Save"), FILE_MENU_SAVE_ANIMATION);
+				file_popup->add_item(TTR("Save As"), FILE_MENU_SAVE_AS_ANIMATION);
+				file_popup->add_separator();
+				file_popup->add_item(TTR("Make Unique"), FILE_MENU_MAKE_ANIMATION_UNIQUE);
+				file_popup->add_separator();
+				file_popup->add_item(TTR("Open in Inspector"), FILE_MENU_EDIT_ANIMATION);
+				Rect2 pos = tree->get_item_rect(p_item, 1, 0);
+				Vector2 popup_pos = tree->get_screen_position() + pos.position + Vector2(0, pos.size.height);
+				file_popup->popup(Rect2(popup_pos, Size2()));
+
+				file_dialog_animation = anim_name;
+				file_dialog_library = lib_name;
+
+			} break;
+			case ANIM_BUTTON_DELETE: {
+				UndoRedo *undo_redo = EditorNode::get_singleton()->get_undo_redo();
+				undo_redo->create_action(vformat(TTR("Remove Animation from Library: %s"), anim_name));
+				undo_redo->add_do_method(al.ptr(), "remove_animation", anim_name);
+				undo_redo->add_undo_method(al.ptr(), "add_animation", anim_name, anim);
+				undo_redo->add_do_method(this, "_update_editor", player);
+				undo_redo->add_undo_method(this, "_update_editor", player);
+				undo_redo->commit_action();
+			} break;
+		}
+	}
+}
+
+void AnimationLibraryEditor::update_tree() {
+	if (updating) {
+		return;
+	}
+
+	tree->clear();
+	ERR_FAIL_COND(!player);
+
+	Color ss_color = get_theme_color(SNAME("prop_subsection"), SNAME("Editor"));
+
+	TreeItem *root = tree->create_item();
+	TypedArray<StringName> libs = player->call("get_animation_library_list");
+
+	for (int i = 0; i < libs.size(); i++) {
+		const StringName K = libs[i];
+		TreeItem *libitem = tree->create_item(root);
+		libitem->set_text(0, K);
+		if (K == StringName()) {
+			libitem->set_suffix(0, TTR("[Global]"));
+		} else {
+			libitem->set_suffix(0, "");
+		}
+		libitem->set_editable(0, true);
+		libitem->set_metadata(0, K);
+		libitem->set_icon(0, get_theme_icon("AnimationLibrary", "EditorIcons"));
+		libitem->add_button(0, get_theme_icon("Add", "EditorIcons"), LIB_BUTTON_ADD, false, TTR("Add Animation to Library"));
+		libitem->add_button(0, get_theme_icon("Load", "EditorIcons"), LIB_BUTTON_LOAD, false, TTR("Load animation from file and add to library"));
+		libitem->add_button(0, get_theme_icon("ActionPaste", "EditorIcons"), LIB_BUTTON_PASTE, false, TTR("Paste Animation to Library from clipboard"));
+		Ref<AnimationLibrary> al = player->call("get_animation_library", K);
+		if (al->get_path().is_resource_file()) {
+			libitem->set_text(1, al->get_path().get_file());
+			libitem->set_tooltip(1, al->get_path());
+		} else {
+			libitem->set_text(1, TTR("[built-in]"));
+		}
+		libitem->add_button(1, get_theme_icon("Save", "EditorIcons"), LIB_BUTTON_FILE, false, TTR("Save animation library to resource on disk"));
+		libitem->add_button(1, get_theme_icon("Remove", "EditorIcons"), LIB_BUTTON_DELETE, false, TTR("Remove animation library"));
+
+		libitem->set_custom_bg_color(0, ss_color);
+
+		List<StringName> animations;
+		al->get_animation_list(&animations);
+		for (const StringName &L : animations) {
+			TreeItem *anitem = tree->create_item(libitem);
+			anitem->set_text(0, L);
+			anitem->set_editable(0, true);
+			anitem->set_metadata(0, L);
+			anitem->set_icon(0, get_theme_icon("Animation", "EditorIcons"));
+			anitem->add_button(0, get_theme_icon("ActionCopy", "EditorIcons"), ANIM_BUTTON_COPY, false, TTR("Copy animation to clipboard"));
+			Ref<Animation> anim = al->get_animation(L);
+
+			if (anim->get_path().is_resource_file()) {
+				anitem->set_text(1, anim->get_path().get_file());
+				anitem->set_tooltip(1, anim->get_path());
+			} else {
+				anitem->set_text(1, TTR("[built-in]"));
+			}
+			anitem->add_button(1, get_theme_icon("Save", "EditorIcons"), ANIM_BUTTON_FILE, false, TTR("Save animation to resource on disk"));
+			anitem->add_button(1, get_theme_icon("Remove", "EditorIcons"), ANIM_BUTTON_DELETE, false, TTR("Remove animation from Library"));
+		}
+	}
+}
+
+void AnimationLibraryEditor::show_dialog() {
+	update_tree();
+	popup_centered_ratio(0.5);
+}
+
+void AnimationLibraryEditor::_update_editor(Object *p_player) {
+	emit_signal("update_editor", p_player);
+}
+
+void AnimationLibraryEditor::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("_update_editor", "player"), &AnimationLibraryEditor::_update_editor);
+	ADD_SIGNAL(MethodInfo("update_editor"));
+}
+
+AnimationLibraryEditor::AnimationLibraryEditor() {
+	set_title(TTR("Edit Animation Libraries"));
+
+	file_dialog = memnew(EditorFileDialog);
+	add_child(file_dialog);
+	file_dialog->connect("file_selected", callable_mp(this, &AnimationLibraryEditor::_load_file));
+
+	add_library_dialog = memnew(ConfirmationDialog);
+	VBoxContainer *dialog_vb = memnew(VBoxContainer);
+	add_library_name = memnew(LineEdit);
+	dialog_vb->add_child(add_library_name);
+	add_library_name->connect("text_changed", callable_mp(this, &AnimationLibraryEditor::_add_library_validate));
+	add_child(add_library_dialog);
+
+	add_library_validate = memnew(Label);
+	dialog_vb->add_child(add_library_validate);
+	add_library_dialog->add_child(dialog_vb);
+	add_library_dialog->connect("confirmed", callable_mp(this, &AnimationLibraryEditor::_add_library_confirm));
+	add_library_dialog->register_text_enter(add_library_name);
+
+	VBoxContainer *vb = memnew(VBoxContainer);
+	HBoxContainer *hb = memnew(HBoxContainer);
+	hb->add_spacer(true);
+	Button *b = memnew(Button(TTR("Add Library")));
+	b->connect("pressed", callable_mp(this, &AnimationLibraryEditor::_add_library));
+	hb->add_child(b);
+	b = memnew(Button(TTR("Load Library")));
+	b->connect("pressed", callable_mp(this, &AnimationLibraryEditor::_load_library));
+	hb->add_child(b);
+	vb->add_child(hb);
+	tree = memnew(Tree);
+	vb->add_child(tree);
+
+	tree->set_columns(2);
+	tree->set_column_titles_visible(true);
+	tree->set_column_title(0, TTR("Resource"));
+	tree->set_column_title(1, TTR("Storage"));
+	tree->set_column_expand(0, true);
+	tree->set_column_custom_minimum_width(1, EDSCALE * 250);
+	tree->set_column_expand(1, false);
+	tree->set_hide_root(true);
+	tree->set_hide_folding(true);
+	tree->set_v_size_flags(Control::SIZE_EXPAND_FILL);
+
+	tree->connect("item_edited", callable_mp(this, &AnimationLibraryEditor::_item_renamed));
+	tree->connect("button_pressed", callable_mp(this, &AnimationLibraryEditor::_button_pressed));
+
+	file_popup = memnew(PopupMenu);
+	add_child(file_popup);
+	file_popup->connect("id_pressed", callable_mp(this, &AnimationLibraryEditor::_file_popup_selected));
+
+	add_child(vb);
+
+	error_dialog = memnew(AcceptDialog);
+	error_dialog->set_title(TTR("Error:"));
+	add_child(error_dialog);
+}
diff --git a/editor/plugins/animation_library_editor.h b/editor/plugins/animation_library_editor.h
new file mode 100644
index 0000000000..5bd4e8d9e2
--- /dev/null
+++ b/editor/plugins/animation_library_editor.h
@@ -0,0 +1,119 @@
+/*************************************************************************/
+/*  animation_library_editor.h                                           */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef ANIMATION_LIBRARY_EDITOR_H
+#define ANIMATION_LIBRARY_EDITOR_H
+
+#include "editor/animation_track_editor.h"
+#include "editor/editor_plugin.h"
+#include "scene/animation/animation_player.h"
+#include "scene/gui/dialogs.h"
+#include "scene/gui/tree.h"
+
+class EditorFileDialog;
+
+class AnimationLibraryEditor : public AcceptDialog {
+	GDCLASS(AnimationLibraryEditor, AcceptDialog)
+
+	enum {
+		LIB_BUTTON_ADD,
+		LIB_BUTTON_LOAD,
+		LIB_BUTTON_PASTE,
+		LIB_BUTTON_FILE,
+		LIB_BUTTON_DELETE,
+	};
+	enum {
+		ANIM_BUTTON_COPY,
+		ANIM_BUTTON_FILE,
+		ANIM_BUTTON_DELETE,
+	};
+
+	enum FileMenuAction {
+		FILE_MENU_SAVE_LIBRARY,
+		FILE_MENU_SAVE_AS_LIBRARY,
+		FILE_MENU_MAKE_LIBRARY_UNIQUE,
+		FILE_MENU_EDIT_LIBRARY,
+
+		FILE_MENU_SAVE_ANIMATION,
+		FILE_MENU_SAVE_AS_ANIMATION,
+		FILE_MENU_MAKE_ANIMATION_UNIQUE,
+		FILE_MENU_EDIT_ANIMATION,
+	};
+
+	enum FileDialogAction {
+		FILE_DIALOG_ACTION_OPEN_LIBRARY,
+		FILE_DIALOG_ACTION_SAVE_LIBRARY,
+		FILE_DIALOG_ACTION_OPEN_ANIMATION,
+		FILE_DIALOG_ACTION_SAVE_ANIMATION,
+	};
+
+	FileDialogAction file_dialog_action = FILE_DIALOG_ACTION_OPEN_ANIMATION;
+
+	StringName file_dialog_animation;
+	StringName file_dialog_library;
+
+	AcceptDialog *error_dialog = nullptr;
+	bool adding_animation = false;
+	StringName adding_animation_to_library;
+	EditorFileDialog *file_dialog = nullptr;
+	ConfirmationDialog *add_library_dialog = nullptr;
+	LineEdit *add_library_name = nullptr;
+	Label *add_library_validate = nullptr;
+	PopupMenu *file_popup = nullptr;
+
+	Tree *tree = nullptr;
+
+	Object *player = nullptr;
+
+	void _add_library();
+	void _add_library_validate(const String &p_name);
+	void _add_library_confirm();
+	void _load_library();
+	void _load_file(String p_path);
+
+	void _item_renamed();
+	void _button_pressed(TreeItem *p_item, int p_column, int p_button);
+
+	void _file_popup_selected(int p_id);
+
+	bool updating = false;
+
+protected:
+	void _update_editor(Object *p_player);
+	static void _bind_methods();
+
+public:
+	void set_animation_player(Object *p_player);
+	void show_dialog();
+	void update_tree();
+	AnimationLibraryEditor();
+};
+
+#endif // ANIMATIONPLAYERLIBRARYEDITOR_H
diff --git a/editor/plugins/animation_player_editor_plugin.cpp b/editor/plugins/animation_player_editor_plugin.cpp
index af7c092d03..2081edca25 100644
--- a/editor/plugins/animation_player_editor_plugin.cpp
+++ b/editor/plugins/animation_player_editor_plugin.cpp
@@ -47,6 +47,8 @@
 #include "scene/scene_string_names.h"
 #include "servers/rendering_server.h"
 
+///////////////////////////////////
+
 void AnimationPlayerEditor::_node_removed(Node *p_node) {
 	if (player && player == p_node) {
 		player = nullptr;
@@ -148,9 +150,7 @@ void AnimationPlayerEditor::_notification(int p_what) {
 #define ITEM_ICON(m_item, m_icon) tool_anim->get_popup()->set_item_icon(tool_anim->get_popup()->get_item_index(m_item), get_theme_icon(SNAME(m_icon), SNAME("EditorIcons")))
 
 			ITEM_ICON(TOOL_NEW_ANIM, "New");
-			ITEM_ICON(TOOL_LOAD_ANIM, "Load");
-			ITEM_ICON(TOOL_SAVE_ANIM, "Save");
-			ITEM_ICON(TOOL_SAVE_AS_ANIM, "Save");
+			ITEM_ICON(TOOL_ANIM_LIBRARY, "AnimationLibrary");
 			ITEM_ICON(TOOL_DUPLICATE_ANIM, "Duplicate");
 			ITEM_ICON(TOOL_RENAME_ANIM, "Rename");
 			ITEM_ICON(TOOL_EDIT_TRANSITIONS, "Blend");
@@ -166,7 +166,7 @@ void AnimationPlayerEditor::_autoplay_pressed() {
 	if (updating) {
 		return;
 	}
-	if (animation->get_item_count() == 0) {
+	if (animation->has_selectable_items() == 0) {
 		return;
 	}
 
@@ -192,10 +192,7 @@ void AnimationPlayerEditor::_autoplay_pressed() {
 }
 
 void AnimationPlayerEditor::_play_pressed() {
-	String current;
-	if (animation->get_selected() >= 0 && animation->get_selected() < animation->get_item_count()) {
-		current = animation->get_item_text(animation->get_selected());
-	}
+	String current = _get_current();
 
 	if (!current.is_empty()) {
 		if (current == player->get_assigned_animation()) {
@@ -209,10 +206,7 @@ void AnimationPlayerEditor::_play_pressed() {
 }
 
 void AnimationPlayerEditor::_play_from_pressed() {
-	String current;
-	if (animation->get_selected() >= 0 && animation->get_selected() < animation->get_item_count()) {
-		current = animation->get_item_text(animation->get_selected());
-	}
+	String current = _get_current();
 
 	if (!current.is_empty()) {
 		float time = player->get_current_animation_position();
@@ -229,12 +223,15 @@ void AnimationPlayerEditor::_play_from_pressed() {
 	stop->set_pressed(false);
 }
 
-void AnimationPlayerEditor::_play_bw_pressed() {
+String AnimationPlayerEditor::_get_current() const {
 	String current;
-	if (animation->get_selected() >= 0 && animation->get_selected() < animation->get_item_count()) {
+	if (animation->get_selected() >= 0 && animation->get_selected() < animation->get_item_count() && !animation->is_item_separator(animation->get_selected())) {
 		current = animation->get_item_text(animation->get_selected());
 	}
-
+	return current;
+}
+void AnimationPlayerEditor::_play_bw_pressed() {
+	String current = _get_current();
 	if (!current.is_empty()) {
 		if (current == player->get_assigned_animation()) {
 			player->stop(); //so it won't blend with itself
@@ -247,10 +244,7 @@ void AnimationPlayerEditor::_play_bw_pressed() {
 }
 
 void AnimationPlayerEditor::_play_bw_from_pressed() {
-	String current;
-	if (animation->get_selected() >= 0 && animation->get_selected() < animation->get_item_count()) {
-		current = animation->get_item_text(animation->get_selected());
-	}
+	String current = _get_current();
 
 	if (!current.is_empty()) {
 		float time = player->get_current_animation_position();
@@ -282,10 +276,7 @@ void AnimationPlayerEditor::_animation_selected(int p_which) {
 	}
 	// when selecting an animation, the idea is that the only interesting behavior
 	// ui-wise is that it should play/blend the next one if currently playing
-	String current;
-	if (animation->get_selected() >= 0 && animation->get_selected() < animation->get_item_count()) {
-		current = animation->get_item_text(animation->get_selected());
-	}
+	String current = _get_current();
 
 	if (!current.is_empty()) {
 		player->set_assigned_animation(current);
@@ -330,6 +321,20 @@ void AnimationPlayerEditor::_animation_new() {
 		break;
 	}
 
+	List<StringName> libraries;
+	player->get_animation_library_list(&libraries);
+	library->clear();
+	for (const StringName &K : libraries) {
+		library->add_item((K == StringName()) ? String(TTR("[Global]")) : String(K));
+		library->set_item_metadata(0, String(K));
+	}
+
+	if (libraries.size() > 1) {
+		library->show();
+	} else {
+		library->hide();
+	}
+
 	name->set_text(base);
 	name_dialog->popup_centered(Size2(300, 90));
 	name->select_all();
@@ -337,7 +342,7 @@ void AnimationPlayerEditor::_animation_new() {
 }
 
 void AnimationPlayerEditor::_animation_rename() {
-	if (animation->get_item_count() == 0) {
+	if (!animation->has_selectable_items()) {
 		return;
 	}
 	int selected = animation->get_selected();
@@ -349,84 +354,11 @@ void AnimationPlayerEditor::_animation_rename() {
 	name_dialog->popup_centered(Size2(300, 90));
 	name->select_all();
 	name->grab_focus();
-}
-
-void AnimationPlayerEditor::_animation_load() {
-	ERR_FAIL_COND(!player);
-	file->set_file_mode(EditorFileDialog::FILE_MODE_OPEN_FILES);
-	file->clear_filters();
-	List<String> extensions;
-
-	ResourceLoader::get_recognized_extensions_for_type("Animation", &extensions);
-	for (const String &E : extensions) {
-		file->add_filter("*." + E + " ; " + E.to_upper());
-	}
-
-	file->popup_file_dialog();
-}
-
-void AnimationPlayerEditor::_animation_save_in_path(const Ref<Resource> &p_resource, const String &p_path) {
-	int flg = 0;
-	if (EditorSettings::get_singleton()->get("filesystem/on_save/compress_binary_resources")) {
-		flg |= ResourceSaver::FLAG_COMPRESS;
-	}
-
-	String path = ProjectSettings::get_singleton()->localize_path(p_path);
-	Error err = ResourceSaver::save(path, p_resource, flg | ResourceSaver::FLAG_REPLACE_SUBRESOURCE_PATHS);
-
-	if (err != OK) {
-		EditorNode::get_singleton()->show_warning(TTR("Error saving resource!"));
-		return;
-	}
-
-	((Resource *)p_resource.ptr())->set_path(path);
-	EditorNode::get_singleton()->emit_signal(SNAME("resource_saved"), p_resource);
-}
-
-void AnimationPlayerEditor::_animation_save(const Ref<Resource> &p_resource) {
-	if (p_resource->get_path().is_resource_file()) {
-		_animation_save_in_path(p_resource, p_resource->get_path());
-	} else {
-		_animation_save_as(p_resource);
-	}
-}
-
-void AnimationPlayerEditor::_animation_save_as(const Ref<Resource> &p_resource) {
-	file->set_file_mode(EditorFileDialog::FILE_MODE_SAVE_FILE);
-
-	List<String> extensions;
-	ResourceSaver::get_recognized_extensions(p_resource, &extensions);
-	file->clear_filters();
-	for (int i = 0; i < extensions.size(); i++) {
-		file->add_filter("*." + extensions[i] + " ; " + extensions[i].to_upper());
-	}
-
-	String path;
-	//file->set_current_path(current_path);
-	if (!p_resource->get_path().is_empty()) {
-		path = p_resource->get_path();
-		if (extensions.size()) {
-			if (extensions.find(p_resource->get_path().get_extension().to_lower()) == nullptr) {
-				path = p_resource->get_path().get_base_dir() + p_resource->get_name() + "." + extensions.front()->get();
-			}
-		}
-	} else {
-		if (extensions.size()) {
-			if (!p_resource->get_name().is_empty()) {
-				path = p_resource->get_name() + "." + extensions.front()->get().to_lower();
-			} else {
-				String resource_name_snake_case = p_resource->get_class().camelcase_to_underscore();
-				path = "new_" + resource_name_snake_case + "." + extensions.front()->get().to_lower();
-			}
-		}
-	}
-	file->set_current_path(path);
-	file->set_title(TTR("Save Resource As..."));
-	file->popup_file_dialog();
+	library->hide();
 }
 
 void AnimationPlayerEditor::_animation_remove() {
-	if (animation->get_item_count() == 0) {
+	if (!animation->has_selectable_items()) {
 		return;
 	}
 
@@ -440,6 +372,9 @@ void AnimationPlayerEditor::_animation_remove_confirmed() {
 	String current = animation->get_item_text(animation->get_selected());
 	Ref<Animation> anim = player->get_animation(current);
 
+	Ref<AnimationLibrary> al = player->get_animation_library(player->find_animation_library(anim));
+	ERR_FAIL_COND(al.is_null());
+
 	undo_redo->create_action(TTR("Remove Animation"));
 	if (player->get_autoplay() == current) {
 		undo_redo->add_do_method(player, "set_autoplay", "");
@@ -447,11 +382,11 @@ void AnimationPlayerEditor::_animation_remove_confirmed() {
 		// Avoid having the autoplay icon linger around if there is only one animation in the player.
 		undo_redo->add_do_method(this, "_animation_player_changed", player);
 	}
-	undo_redo->add_do_method(player, "remove_animation", current);
-	undo_redo->add_undo_method(player, "add_animation", current, anim);
+	undo_redo->add_do_method(al.ptr(), "remove_animation", current);
+	undo_redo->add_undo_method(al.ptr(), "add_animation", current, anim);
 	undo_redo->add_do_method(this, "_animation_player_changed", player);
 	undo_redo->add_undo_method(this, "_animation_player_changed", player);
-	if (animation->get_item_count() == 1) {
+	if (animation->has_selectable_items() && animation->get_selectable_item(false) == animation->get_selectable_item(true)) { // Last item remaining.
 		undo_redo->add_do_method(this, "_stop_onion_skinning");
 		undo_redo->add_undo_method(this, "_start_onion_skinning");
 	}
@@ -498,7 +433,7 @@ void AnimationPlayerEditor::_animation_name_edited() {
 		return;
 	}
 
-	if (name_dialog_op == TOOL_RENAME_ANIM && animation->get_item_count() > 0 && animation->get_item_text(animation->get_selected()) == new_name) {
+	if (name_dialog_op == TOOL_RENAME_ANIM && animation->has_selectable_items() && animation->get_item_text(animation->get_selected()) == new_name) {
 		name_dialog->hide();
 		return;
 	}
@@ -514,10 +449,13 @@ void AnimationPlayerEditor::_animation_name_edited() {
 			String current = animation->get_item_text(animation->get_selected());
 			Ref<Animation> anim = player->get_animation(current);
 
+			Ref<AnimationLibrary> al = player->get_animation_library(player->find_animation_library(anim));
+			ERR_FAIL_COND(al.is_null());
+
 			undo_redo->create_action(TTR("Rename Animation"));
-			undo_redo->add_do_method(player, "rename_animation", current, new_name);
+			undo_redo->add_do_method(al.ptr(), "rename_animation", current, new_name);
 			undo_redo->add_do_method(anim.ptr(), "set_name", new_name);
-			undo_redo->add_undo_method(player, "rename_animation", new_name, current);
+			undo_redo->add_undo_method(al.ptr(), "rename_animation", new_name, current);
 			undo_redo->add_undo_method(anim.ptr(), "set_name", current);
 			undo_redo->add_do_method(this, "_animation_player_changed", player);
 			undo_redo->add_undo_method(this, "_animation_player_changed", player);
@@ -530,15 +468,35 @@ void AnimationPlayerEditor::_animation_name_edited() {
 			Ref<Animation> new_anim = Ref<Animation>(memnew(Animation));
 			new_anim->set_name(new_name);
 
+			Ref<AnimationLibrary> al;
+			if (library->is_visible()) {
+				al = player->get_animation_library(library->get_item_metadata(library->get_selected()));
+			} else {
+				if (player->has_animation_library("")) {
+					al = player->get_animation_library("");
+				}
+			}
+
 			undo_redo->create_action(TTR("Add Animation"));
-			undo_redo->add_do_method(player, "add_animation", new_name, new_anim);
-			undo_redo->add_undo_method(player, "remove_animation", new_name);
+
+			bool lib_added = false;
+			if (al.is_null()) {
+				al.instantiate();
+				lib_added = true;
+				undo_redo->add_do_method(player, "add_animation_library", "", al);
+			}
+
+			undo_redo->add_do_method(al.ptr(), "add_animation", new_name, new_anim);
+			undo_redo->add_undo_method(al.ptr(), "remove_animation", new_name);
 			undo_redo->add_do_method(this, "_animation_player_changed", player);
 			undo_redo->add_undo_method(this, "_animation_player_changed", player);
-			if (animation->get_item_count() == 0) {
+			if (!animation->has_selectable_items()) {
 				undo_redo->add_do_method(this, "_start_onion_skinning");
 				undo_redo->add_undo_method(this, "_stop_onion_skinning");
 			}
+			if (lib_added) {
+				undo_redo->add_undo_method(player, "remove_animation_library", "");
+			}
 			undo_redo->commit_action();
 
 			_select_anim_by_name(new_name);
@@ -551,9 +509,11 @@ void AnimationPlayerEditor::_animation_name_edited() {
 			Ref<Animation> new_anim = _animation_clone(anim);
 			new_anim->set_name(new_name);
 
+			Ref<AnimationLibrary> library = player->get_animation_library(player->find_animation_library(anim));
+
 			undo_redo->create_action(TTR("Duplicate Animation"));
-			undo_redo->add_do_method(player, "add_animation", new_name, new_anim);
-			undo_redo->add_undo_method(player, "remove_animation", new_name);
+			undo_redo->add_do_method(library.ptr(), "add_animation", new_name, new_anim);
+			undo_redo->add_undo_method(library.ptr(), "remove_animation", new_name);
 			undo_redo->add_do_method(player, "animation_set_next", new_name, player->animation_get_next(current));
 			undo_redo->add_do_method(this, "_animation_player_changed", player);
 			undo_redo->add_undo_method(this, "_animation_player_changed", player);
@@ -567,7 +527,7 @@ void AnimationPlayerEditor::_animation_name_edited() {
 }
 
 void AnimationPlayerEditor::_blend_editor_next_changed(const int p_idx) {
-	if (animation->get_item_count() == 0) {
+	if (!animation->has_selectable_items()) {
 		return;
 	}
 
@@ -588,7 +548,7 @@ void AnimationPlayerEditor::_animation_blend() {
 
 	blend_editor.tree->clear();
 
-	if (animation->get_item_count() == 0) {
+	if (!animation->has_selectable_items()) {
 		return;
 	}
 
@@ -643,7 +603,7 @@ void AnimationPlayerEditor::_blend_edited() {
 		return;
 	}
 
-	if (animation->get_item_count() == 0) {
+	if (!animation->has_selectable_items()) {
 		return;
 	}
 
@@ -722,16 +682,16 @@ void AnimationPlayerEditor::set_state(const Dictionary &p_state) {
 }
 
 void AnimationPlayerEditor::_animation_resource_edit() {
-	if (animation->get_item_count()) {
-		String current = animation->get_item_text(animation->get_selected());
+	String current = _get_current();
+	if (current != String()) {
 		Ref<Animation> anim = player->get_animation(current);
 		EditorNode::get_singleton()->edit_resource(anim);
 	}
 }
 
 void AnimationPlayerEditor::_animation_edit() {
-	if (animation->get_item_count()) {
-		String current = animation->get_item_text(animation->get_selected());
+	String current = _get_current();
+	if (current != String()) {
 		Ref<Animation> anim = player->get_animation(current);
 		track_editor->set_animation(anim);
 
@@ -745,51 +705,6 @@ void AnimationPlayerEditor::_animation_edit() {
 	}
 }
 
-void AnimationPlayerEditor::_save_animation(String p_file) {
-	String current = animation->get_item_text(animation->get_selected());
-	if (!current.is_empty()) {
-		Ref<Animation> anim = player->get_animation(current);
-
-		ERR_FAIL_COND(!Object::cast_to<Resource>(*anim));
-
-		RES current_res = RES(Object::cast_to<Resource>(*anim));
-
-		_animation_save_in_path(current_res, p_file);
-	}
-}
-
-void AnimationPlayerEditor::_load_animations(Vector<String> p_files) {
-	ERR_FAIL_COND(!player);
-
-	for (int i = 0; i < p_files.size(); i++) {
-		String file = p_files[i];
-
-		Ref<Resource> res = ResourceLoader::load(file, "Animation");
-		ERR_FAIL_COND_MSG(res.is_null(), "Cannot load Animation from file '" + file + "'.");
-		ERR_FAIL_COND_MSG(!res->is_class("Animation"), "Loaded resource from file '" + file + "' is not Animation.");
-		if (file.rfind("/") != -1) {
-			file = file.substr(file.rfind("/") + 1, file.length());
-		}
-		if (file.rfind("\\") != -1) {
-			file = file.substr(file.rfind("\\") + 1, file.length());
-		}
-
-		if (file.contains(".")) {
-			file = file.substr(0, file.find("."));
-		}
-
-		undo_redo->create_action(TTR("Load Animation"));
-		undo_redo->add_do_method(player, "add_animation", file, res);
-		undo_redo->add_undo_method(player, "remove_animation", file);
-		if (player->has_animation(file)) {
-			undo_redo->add_undo_method(player, "add_animation", file, player->get_animation(file));
-		}
-		undo_redo->add_do_method(this, "_animation_player_changed", player);
-		undo_redo->add_undo_method(this, "_animation_player_changed", player);
-		undo_redo->commit_action();
-	}
-}
-
 void AnimationPlayerEditor::_scale_changed(const String &p_scale) {
 	player->set_speed_scale(p_scale.to_float());
 }
@@ -824,49 +739,66 @@ void AnimationPlayerEditor::_update_animation() {
 
 void AnimationPlayerEditor::_update_player() {
 	updating = true;
-	List<StringName> animlist;
-	if (player) {
-		player->get_animation_list(&animlist);
-	}
 
 	animation->clear();
 
-#define ITEM_DISABLED(m_item, m_disabled) tool_anim->get_popup()->set_item_disabled(tool_anim->get_popup()->get_item_index(m_item), m_disabled)
-
-	ITEM_DISABLED(TOOL_SAVE_ANIM, animlist.size() == 0);
-	ITEM_DISABLED(TOOL_SAVE_AS_ANIM, animlist.size() == 0);
-	ITEM_DISABLED(TOOL_DUPLICATE_ANIM, animlist.size() == 0);
-	ITEM_DISABLED(TOOL_RENAME_ANIM, animlist.size() == 0);
-	ITEM_DISABLED(TOOL_EDIT_TRANSITIONS, animlist.size() == 0);
-	ITEM_DISABLED(TOOL_COPY_ANIM, animlist.size() == 0);
-	ITEM_DISABLED(TOOL_REMOVE_ANIM, animlist.size() == 0);
-
-	stop->set_disabled(animlist.size() == 0);
-	play->set_disabled(animlist.size() == 0);
-	play_bw->set_disabled(animlist.size() == 0);
-	play_bw_from->set_disabled(animlist.size() == 0);
-	play_from->set_disabled(animlist.size() == 0);
-	frame->set_editable(animlist.size() != 0);
-	animation->set_disabled(animlist.size() == 0);
-	autoplay->set_disabled(animlist.size() == 0);
-	tool_anim->set_disabled(player == nullptr);
-	onion_toggle->set_disabled(animlist.size() == 0);
-	onion_skinning->set_disabled(animlist.size() == 0);
-	pin->set_disabled(player == nullptr);
-
 	if (!player) {
 		AnimationPlayerEditor::get_singleton()->get_track_editor()->update_keying();
 		return;
 	}
 
+	List<StringName> libraries;
+	if (player) {
+		player->get_animation_library_list(&libraries);
+	}
+
 	int active_idx = -1;
-	for (const StringName &E : animlist) {
-		animation->add_item(E);
+	bool no_anims_found = true;
 
-		if (player->get_assigned_animation() == E) {
-			active_idx = animation->get_item_count() - 1;
+	for (const StringName &K : libraries) {
+		if (K != StringName()) {
+			animation->add_separator(K);
+		}
+
+		Ref<AnimationLibrary> library = player->get_animation_library(K);
+		List<StringName> animlist;
+		library->get_animation_list(&animlist);
+
+		for (const StringName &E : animlist) {
+			String path = K;
+			if (path != "") {
+				path += "/";
+			}
+			path += E;
+			animation->add_item(path);
+			if (player->get_assigned_animation() == path) {
+				active_idx = animation->get_selectable_item(true);
+			}
+			no_anims_found = false;
 		}
 	}
+#define ITEM_CHECK_DISABLED(m_item) tool_anim->get_popup()->set_item_disabled(tool_anim->get_popup()->get_item_index(m_item), no_anims_found)
+
+	ITEM_CHECK_DISABLED(TOOL_DUPLICATE_ANIM);
+	ITEM_CHECK_DISABLED(TOOL_RENAME_ANIM);
+	ITEM_CHECK_DISABLED(TOOL_EDIT_TRANSITIONS);
+	ITEM_CHECK_DISABLED(TOOL_REMOVE_ANIM);
+
+#undef ITEM_CHECK_DISABLED
+
+	stop->set_disabled(no_anims_found);
+	play->set_disabled(no_anims_found);
+	play_bw->set_disabled(no_anims_found);
+	play_bw_from->set_disabled(no_anims_found);
+	play_from->set_disabled(no_anims_found);
+	frame->set_editable(!no_anims_found);
+	animation->set_disabled(no_anims_found);
+	autoplay->set_disabled(no_anims_found);
+	tool_anim->set_disabled(player == nullptr);
+	onion_toggle->set_disabled(no_anims_found);
+	onion_skinning->set_disabled(no_anims_found);
+	pin->set_disabled(player == nullptr);
+
 	_update_animation_list_icons();
 
 	updating = false;
@@ -874,16 +806,16 @@ void AnimationPlayerEditor::_update_player() {
 		animation->select(active_idx);
 		autoplay->set_pressed(animation->get_item_text(active_idx) == player->get_autoplay());
 		_animation_selected(active_idx);
-
-	} else if (animation->get_item_count() > 0) {
-		animation->select(0);
-		autoplay->set_pressed(animation->get_item_text(0) == player->get_autoplay());
-		_animation_selected(0);
+	} else if (animation->has_selectable_items()) {
+		int item = animation->get_selectable_item();
+		animation->select(item);
+		autoplay->set_pressed(animation->get_item_text(item) == player->get_autoplay());
+		_animation_selected(item);
 	} else {
 		_animation_selected(0);
 	}
 
-	if (animation->get_item_count()) {
+	if (!no_anims_found) {
 		String current = animation->get_item_text(animation->get_selected());
 		Ref<Animation> anim = player->get_animation(current);
 		track_editor->set_animation(anim);
@@ -899,6 +831,9 @@ void AnimationPlayerEditor::_update_player() {
 void AnimationPlayerEditor::_update_animation_list_icons() {
 	for (int i = 0; i < animation->get_item_count(); i++) {
 		String name = animation->get_item_text(i);
+		if (animation->is_item_disabled(i) || animation->is_item_separator(i)) {
+			continue;
+		}
 
 		Ref<Texture2D> icon;
 		if (name == player->get_autoplay()) {
@@ -925,7 +860,7 @@ void AnimationPlayerEditor::edit(AnimationPlayer *p_player) {
 		_update_player();
 
 		if (onion.enabled) {
-			if (animation->get_item_count() > 0) {
+			if (animation->has_selectable_items()) {
 				_start_onion_skinning();
 			} else {
 				_stop_onion_skinning();
@@ -940,6 +875,8 @@ void AnimationPlayerEditor::edit(AnimationPlayer *p_player) {
 
 		track_editor->show_select_node_warning(true);
 	}
+
+	library_editor->set_animation_player(player);
 }
 
 void AnimationPlayerEditor::forward_force_draw_over_viewport(Control *p_overlay) {
@@ -993,7 +930,7 @@ void AnimationPlayerEditor::forward_force_draw_over_viewport(Control *p_overlay)
 }
 
 void AnimationPlayerEditor::_animation_duplicate() {
-	if (!animation->get_item_count()) {
+	if (!animation->has_selectable_items()) {
 		return;
 	}
 
@@ -1031,29 +968,6 @@ Ref<Animation> AnimationPlayerEditor::_animation_clone(Ref<Animation> p_anim) {
 	return new_anim;
 }
 
-void AnimationPlayerEditor::_animation_paste(Ref<Animation> p_anim) {
-	String name = p_anim->get_name();
-	if (name.is_empty()) {
-		name = TTR("Pasted Animation");
-	}
-
-	int idx = 1;
-	String base = name;
-	while (player->has_animation(name)) {
-		idx++;
-		name = base + " " + itos(idx);
-	}
-
-	undo_redo->create_action(TTR("Paste Animation"));
-	undo_redo->add_do_method(player, "add_animation", name, p_anim);
-	undo_redo->add_undo_method(player, "remove_animation", name);
-	undo_redo->add_do_method(this, "_animation_player_changed", player);
-	undo_redo->add_undo_method(this, "_animation_player_changed", player);
-	undo_redo->commit_action();
-
-	_select_anim_by_name(name);
-}
-
 void AnimationPlayerEditor::_seek_value_changed(float p_value, bool p_set, bool p_timeline_only) {
 	if (updating || !player || player->is_playing()) {
 		return;
@@ -1095,6 +1009,9 @@ void AnimationPlayerEditor::_animation_player_changed(Object *p_pl) {
 		if (blend_editor.dialog->is_visible()) {
 			_animation_blend(); // Update.
 		}
+		if (library_editor->is_visible()) {
+			library_editor->update_tree();
+		}
 	}
 }
 
@@ -1134,10 +1051,7 @@ void AnimationPlayerEditor::_animation_key_editor_seek(float p_pos, bool p_drag,
 }
 
 void AnimationPlayerEditor::_animation_tool_menu(int p_option) {
-	String current;
-	if (animation->get_selected() >= 0 && animation->get_selected() < animation->get_item_count()) {
-		current = animation->get_item_text(animation->get_selected());
-	}
+	String current = _get_current();
 
 	Ref<Animation> anim;
 	if (!current.is_empty()) {
@@ -1148,18 +1062,9 @@ void AnimationPlayerEditor::_animation_tool_menu(int p_option) {
 		case TOOL_NEW_ANIM: {
 			_animation_new();
 		} break;
-		case TOOL_LOAD_ANIM: {
-			_animation_load();
-		} break;
-		case TOOL_SAVE_ANIM: {
-			if (anim.is_valid()) {
-				_animation_save(anim);
-			}
-		} break;
-		case TOOL_SAVE_AS_ANIM: {
-			if (anim.is_valid()) {
-				_animation_save_as(anim);
-			}
+		case TOOL_ANIM_LIBRARY: {
+			library_editor->set_animation_player(player);
+			library_editor->show_dialog();
 		} break;
 		case TOOL_DUPLICATE_ANIM: {
 			_animation_duplicate();
@@ -1173,39 +1078,8 @@ void AnimationPlayerEditor::_animation_tool_menu(int p_option) {
 		case TOOL_REMOVE_ANIM: {
 			_animation_remove();
 		} break;
-		case TOOL_COPY_ANIM: {
-			if (!animation->get_item_count()) {
-				error_dialog->set_text(TTR("No animation to copy!"));
-				error_dialog->popup_centered();
-				return;
-			}
-
-			String current2 = animation->get_item_text(animation->get_selected());
-			Ref<Animation> anim2 = player->get_animation(current2);
-			EditorSettings::get_singleton()->set_resource_clipboard(anim2);
-		} break;
-		case TOOL_PASTE_ANIM: {
-			Ref<Animation> anim2 = EditorSettings::get_singleton()->get_resource_clipboard();
-			if (!anim2.is_valid()) {
-				error_dialog->set_text(TTR("No animation resource in clipboard!"));
-				error_dialog->popup_centered();
-				return;
-			}
-			Ref<Animation> new_anim = _animation_clone(anim2);
-			_animation_paste(new_anim);
-		} break;
-		case TOOL_PASTE_ANIM_REF: {
-			Ref<Animation> anim2 = EditorSettings::get_singleton()->get_resource_clipboard();
-			if (!anim2.is_valid()) {
-				error_dialog->set_text(TTR("No animation resource in clipboard!"));
-				error_dialog->popup_centered();
-				return;
-			}
-
-			_animation_paste(anim2);
-		} break;
 		case TOOL_EDIT_RESOURCE: {
-			if (!animation->get_item_count()) {
+			if (!animation->has_selectable_items()) {
 				error_dialog->set_text(TTR("No animation to edit!"));
 				error_dialog->popup_centered();
 				return;
@@ -1300,7 +1174,7 @@ void AnimationPlayerEditor::shortcut_input(const Ref<InputEvent> &p_ev) {
 }
 
 void AnimationPlayerEditor::_editor_visibility_changed() {
-	if (is_visible() && animation->get_item_count() > 0) {
+	if (is_visible() && animation->has_selectable_items()) {
 		_start_onion_skinning();
 	}
 }
@@ -1536,7 +1410,6 @@ void AnimationPlayerEditor::_pin_pressed() {
 void AnimationPlayerEditor::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("_animation_new"), &AnimationPlayerEditor::_animation_new);
 	ClassDB::bind_method(D_METHOD("_animation_rename"), &AnimationPlayerEditor::_animation_rename);
-	ClassDB::bind_method(D_METHOD("_animation_load"), &AnimationPlayerEditor::_animation_load);
 	ClassDB::bind_method(D_METHOD("_animation_remove"), &AnimationPlayerEditor::_animation_remove);
 	ClassDB::bind_method(D_METHOD("_animation_blend"), &AnimationPlayerEditor::_animation_blend);
 	ClassDB::bind_method(D_METHOD("_animation_edit"), &AnimationPlayerEditor::_animation_edit);
@@ -1623,13 +1496,7 @@ AnimationPlayerEditor::AnimationPlayerEditor(AnimationPlayerEditorPlugin *p_plug
 	tool_anim->set_text(TTR("Animation"));
 	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/new_animation", TTR("New")), TOOL_NEW_ANIM);
 	tool_anim->get_popup()->add_separator();
-	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/open_animation", TTR("Load")), TOOL_LOAD_ANIM);
-	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/save_animation", TTR("Save")), TOOL_SAVE_ANIM);
-	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/save_as_animation", TTR("Save As...")), TOOL_SAVE_AS_ANIM);
-	tool_anim->get_popup()->add_separator();
-	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/copy_animation", TTR("Copy")), TOOL_COPY_ANIM);
-	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/paste_animation", TTR("Paste")), TOOL_PASTE_ANIM);
-	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/paste_animation_as_reference", TTR("Paste As Reference")), TOOL_PASTE_ANIM_REF);
+	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/animation_libraries", TTR("Manage Animations...")), TOOL_ANIM_LIBRARY);
 	tool_anim->get_popup()->add_separator();
 	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/duplicate_animation", TTR("Duplicate...")), TOOL_DUPLICATE_ANIM);
 	tool_anim->get_popup()->add_separator();
@@ -1638,6 +1505,7 @@ AnimationPlayerEditor::AnimationPlayerEditor(AnimationPlayerEditorPlugin *p_plug
 	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/open_animation_in_inspector", TTR("Open in Inspector")), TOOL_EDIT_RESOURCE);
 	tool_anim->get_popup()->add_separator();
 	tool_anim->get_popup()->add_shortcut(ED_SHORTCUT("animation_player_editor/remove_animation", TTR("Remove")), TOOL_REMOVE_ANIM);
+	tool_anim->set_disabled(true);
 	hb->add_child(tool_anim);
 
 	animation = memnew(OptionButton);
@@ -1705,8 +1573,14 @@ AnimationPlayerEditor::AnimationPlayerEditor(AnimationPlayerEditorPlugin *p_plug
 	name_title = memnew(Label(TTR("Animation Name:")));
 	vb->add_child(name_title);
 
+	HBoxContainer *name_hb = memnew(HBoxContainer);
 	name = memnew(LineEdit);
-	vb->add_child(name);
+	name_hb->add_child(name);
+	name->set_h_size_flags(SIZE_EXPAND_FILL);
+	library = memnew(OptionButton);
+	name_hb->add_child(library);
+	library->hide();
+	vb->add_child(name_hb);
 	name_dialog->register_text_enter(name);
 
 	error_dialog = memnew(ConfirmationDialog);
@@ -1742,8 +1616,6 @@ AnimationPlayerEditor::AnimationPlayerEditor(AnimationPlayerEditorPlugin *p_plug
 
 	animation->connect("item_selected", callable_mp(this, &AnimationPlayerEditor::_animation_selected));
 
-	file->connect("file_selected", callable_mp(this, &AnimationPlayerEditor::_save_animation));
-	file->connect("files_selected", callable_mp(this, &AnimationPlayerEditor::_load_animations));
 	frame->connect("value_changed", callable_mp(this, &AnimationPlayerEditor::_seek_value_changed), make_binds(true, false));
 	scale->connect("text_submitted", callable_mp(this, &AnimationPlayerEditor::_scale_changed));
 
@@ -1759,6 +1631,10 @@ AnimationPlayerEditor::AnimationPlayerEditor(AnimationPlayerEditorPlugin *p_plug
 
 	_update_player();
 
+	library_editor = memnew(AnimationLibraryEditor);
+	add_child(library_editor);
+	library_editor->connect("update_editor", callable_mp(this, &AnimationPlayerEditor::_animation_player_changed));
+
 	// Onion skinning.
 
 	track_editor->connect("visibility_changed", callable_mp(this, &AnimationPlayerEditor::_editor_visibility_changed));
diff --git a/editor/plugins/animation_player_editor_plugin.h b/editor/plugins/animation_player_editor_plugin.h
index 4f6a9c534f..0cc04460ca 100644
--- a/editor/plugins/animation_player_editor_plugin.h
+++ b/editor/plugins/animation_player_editor_plugin.h
@@ -33,6 +33,7 @@
 
 #include "editor/animation_track_editor.h"
 #include "editor/editor_plugin.h"
+#include "editor/plugins/animation_library_editor.h"
 #include "scene/animation/animation_player.h"
 #include "scene/gui/dialogs.h"
 #include "scene/gui/slider.h"
@@ -40,7 +41,6 @@
 #include "scene/gui/texture_button.h"
 #include "scene/gui/tree.h"
 
-class EditorFileDialog;
 class AnimationPlayerEditorPlugin;
 
 class AnimationPlayerEditor : public VBoxContainer {
@@ -51,16 +51,11 @@ class AnimationPlayerEditor : public VBoxContainer {
 
 	enum {
 		TOOL_NEW_ANIM,
-		TOOL_LOAD_ANIM,
-		TOOL_SAVE_ANIM,
-		TOOL_SAVE_AS_ANIM,
+		TOOL_ANIM_LIBRARY,
 		TOOL_DUPLICATE_ANIM,
 		TOOL_RENAME_ANIM,
 		TOOL_EDIT_TRANSITIONS,
 		TOOL_REMOVE_ANIM,
-		TOOL_COPY_ANIM,
-		TOOL_PASTE_ANIM,
-		TOOL_PASTE_ANIM_REF,
 		TOOL_EDIT_RESOURCE
 	};
 
@@ -103,8 +98,10 @@ class AnimationPlayerEditor : public VBoxContainer {
 	SpinBox *frame = nullptr;
 	LineEdit *scale = nullptr;
 	LineEdit *name = nullptr;
+	OptionButton *library = nullptr;
 	Label *name_title = nullptr;
 	UndoRedo *undo_redo = nullptr;
+
 	Ref<Texture2D> autoplay_icon;
 	Ref<Texture2D> reset_icon;
 	Ref<ImageTexture> autoplay_reset_icon;
@@ -114,6 +111,8 @@ class AnimationPlayerEditor : public VBoxContainer {
 	EditorFileDialog *file = nullptr;
 	ConfirmationDialog *delete_dialog = nullptr;
 
+	AnimationLibraryEditor *library_editor = nullptr;
+
 	struct BlendEditor {
 		AcceptDialog *dialog = nullptr;
 		Tree *tree = nullptr;
@@ -173,11 +172,6 @@ class AnimationPlayerEditor : public VBoxContainer {
 	void _animation_new();
 	void _animation_rename();
 	void _animation_name_edited();
-	void _animation_load();
-
-	void _animation_save_in_path(const Ref<Resource> &p_resource, const String &p_path);
-	void _animation_save(const Ref<Resource> &p_resource);
-	void _animation_save_as(const Ref<Resource> &p_resource);
 
 	void _animation_remove();
 	void _animation_remove_confirmed();
@@ -185,11 +179,8 @@ class AnimationPlayerEditor : public VBoxContainer {
 	void _animation_edit();
 	void _animation_duplicate();
 	Ref<Animation> _animation_clone(const Ref<Animation> p_anim);
-	void _animation_paste(const Ref<Animation> p_anim);
 	void _animation_resource_edit();
 	void _scale_changed(const String &p_scale);
-	void _save_animation(String p_file);
-	void _load_animations(Vector<String> p_files);
 	void _seek_value_changed(float p_value, bool p_set = false, bool p_timeline_only = false);
 	void _blend_editor_next_changed(const int p_idx);
 
@@ -219,6 +210,7 @@ class AnimationPlayerEditor : public VBoxContainer {
 	void _stop_onion_skinning();
 
 	void _pin_pressed();
+	String _get_current() const;
 
 	~AnimationPlayerEditor();
 
diff --git a/modules/gltf/gltf_document.cpp b/modules/gltf/gltf_document.cpp
index ee756c6d2e..fe00f565be 100644
--- a/modules/gltf/gltf_document.cpp
+++ b/modules/gltf/gltf_document.cpp
@@ -6097,7 +6097,14 @@ void GLTFDocument::_import_animation(Ref<GLTFState> state, AnimationPlayer *ap,
 
 	animation->set_length(length);
 
-	ap->add_animation(name, animation);
+	Ref<AnimationLibrary> library;
+	if (!ap->has_animation_library("")) {
+		library.instantiate();
+		ap->add_animation_library("", library);
+	} else {
+		library = ap->get_animation_library("");
+	}
+	library->add_animation(name, animation);
 }
 
 void GLTFDocument::_convert_mesh_instances(Ref<GLTFState> state) {
diff --git a/scene/animation/animation_player.cpp b/scene/animation/animation_player.cpp
index 1ab2e2419e..6949e3681c 100644
--- a/scene/animation/animation_player.cpp
+++ b/scene/animation/animation_player.cpp
@@ -83,8 +83,31 @@ bool AnimationPlayer::_set(const StringName &p_name, const Variant &p_value) {
 		set_current_animation(p_value);
 
 	} else if (name.begins_with("anims/")) {
+		// Backwards compatibility with 3.x, add them to "default" library.
 		String which = name.get_slicec('/', 1);
-		add_animation(which, p_value);
+
+		Ref<Animation> anim = p_value;
+		Ref<AnimationLibrary> al;
+		if (!has_animation_library(StringName())) {
+			al.instantiate();
+			add_animation_library(StringName(), al);
+		} else {
+			al = get_animation_library(StringName());
+		}
+		al->add_animation(which, anim);
+
+	} else if (name.begins_with("libraries")) {
+		Dictionary d = p_value;
+		while (animation_libraries.size()) {
+			remove_animation_library(animation_libraries[0].name);
+		}
+		List<Variant> keys;
+		d.get_key_list(&keys);
+		for (const Variant &K : keys) {
+			StringName lib_name = K;
+			Ref<AnimationLibrary> lib = d[lib_name];
+			add_animation_library(lib_name, lib);
+		}
 
 	} else if (name.begins_with("next/")) {
 		String which = name.get_slicec('/', 1);
@@ -117,9 +140,13 @@ bool AnimationPlayer::_get(const StringName &p_name, Variant &r_ret) const {
 
 		r_ret = get_current_animation();
 
-	} else if (name.begins_with("anims/")) {
-		String which = name.get_slicec('/', 1);
-		r_ret = get_animation(which);
+	} else if (name.begins_with("libraries")) {
+		Dictionary d;
+		for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+			d[animation_libraries[i].name] = animation_libraries[i].library;
+		}
+
+		r_ret = d;
 
 	} else if (name.begins_with("next/")) {
 		String which = name.get_slicec('/', 1);
@@ -173,8 +200,9 @@ void AnimationPlayer::_validate_property(PropertyInfo &property) const {
 void AnimationPlayer::_get_property_list(List<PropertyInfo> *p_list) const {
 	List<PropertyInfo> anim_names;
 
+	anim_names.push_back(PropertyInfo(Variant::DICTIONARY, "libraries"));
+
 	for (const KeyValue<StringName, AnimationData> &E : animation_set) {
-		anim_names.push_back(PropertyInfo(Variant::OBJECT, "anims/" + String(E.key), PROPERTY_HINT_RESOURCE_TYPE, "Animation", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL | PROPERTY_USAGE_DO_NOT_SHARE_ON_DUPLICATE));
 		if (E.value.next != StringName()) {
 			anim_names.push_back(PropertyInfo(Variant::STRING, "next/" + String(E.key), PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
 		}
@@ -1155,71 +1183,106 @@ void AnimationPlayer::_animation_process(double p_delta) {
 	}
 }
 
-Error AnimationPlayer::add_animation(const StringName &p_name, const Ref<Animation> &p_animation) {
-#ifdef DEBUG_ENABLED
-	ERR_FAIL_COND_V_MSG(String(p_name).contains("/") || String(p_name).contains(":") || String(p_name).contains(",") || String(p_name).contains("["), ERR_INVALID_PARAMETER, "Invalid animation name: " + String(p_name) + ".");
-#endif
+void AnimationPlayer::_animation_set_cache_update() {
+	// Relatively fast function to update all animations.
 
-	ERR_FAIL_COND_V(p_animation.is_null(), ERR_INVALID_PARAMETER);
+	animation_set_update_pass++;
+	bool clear_cache_needed = false;
 
-	if (animation_set.has(p_name)) {
-		_unref_anim(animation_set[p_name].animation);
-		animation_set[p_name].animation = p_animation;
-		clear_caches();
-	} else {
-		AnimationData ad;
-		ad.animation = p_animation;
-		ad.name = p_name;
-		animation_set[p_name] = ad;
-	}
+	// Update changed and add otherwise
+	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+		for (const KeyValue<StringName, Ref<Animation>> &K : animation_libraries[i].library->animations) {
+			StringName key = animation_libraries[i].name == StringName() ? K.key : StringName(String(animation_libraries[i].name) + "/" + String(K.key));
+			if (!animation_set.has(key)) {
+				AnimationData ad;
+				ad.animation = K.value;
+				ad.animation_library = animation_libraries[i].name;
+				ad.name = key;
+				ad.last_update = animation_set_update_pass;
+				animation_set.insert(ad.name, ad);
+			} else {
+				AnimationData &ad = animation_set[key];
+				if (ad.last_update != animation_set_update_pass) {
+					// Was not updated, update. If the animation is duplicated, the second one will be ignored.
+					if (ad.animation != K.value || ad.animation_library != animation_libraries[i].name) {
+						// Animation changed, update and clear caches.
+						clear_cache_needed = true;
+						ad.animation = K.value;
+						ad.animation_library = animation_libraries[i].name;
+					}
 
-	_ref_anim(p_animation);
-	notify_property_list_changed();
-	return OK;
-}
+					ad.last_update = animation_set_update_pass;
+				}
+			}
+		}
+	}
 
-void AnimationPlayer::remove_animation(const StringName &p_name) {
-	ERR_FAIL_COND(!animation_set.has(p_name));
+	// Check removed
+	List<StringName> to_erase;
+	for (const KeyValue<StringName, AnimationData> &E : animation_set) {
+		if (E.value.last_update != animation_set_update_pass) {
+			// Was not updated, must be erased
+			to_erase.push_back(E.key);
+			clear_cache_needed = true;
+		}
+	}
 
-	stop();
-	_unref_anim(animation_set[p_name].animation);
-	animation_set.erase(p_name);
+	while (to_erase.size()) {
+		animation_set.erase(to_erase.front()->get());
+		to_erase.pop_front();
+	}
 
-	clear_caches();
-	notify_property_list_changed();
+	if (clear_cache_needed) {
+		// If something was modified or removed, caches need to be cleared
+		clear_caches();
+	}
 }
 
-void AnimationPlayer::_ref_anim(const Ref<Animation> &p_anim) {
-	Ref<Animation>(p_anim)->connect(SceneStringNames::get_singleton()->tracks_changed, callable_mp(this, &AnimationPlayer::_animation_changed), varray(), CONNECT_REFERENCE_COUNTED);
-}
+void AnimationPlayer::_animation_added(const StringName &p_name, const StringName &p_library) {
+	_animation_set_cache_update();
 
-void AnimationPlayer::_unref_anim(const Ref<Animation> &p_anim) {
-	Ref<Animation>(p_anim)->disconnect(SceneStringNames::get_singleton()->tracks_changed, callable_mp(this, &AnimationPlayer::_animation_changed));
+	update_configuration_warnings();
 }
 
-void AnimationPlayer::rename_animation(const StringName &p_name, const StringName &p_new_name) {
-	ERR_FAIL_COND(!animation_set.has(p_name));
-	ERR_FAIL_COND(String(p_new_name).contains("/") || String(p_new_name).contains(":"));
-	ERR_FAIL_COND(animation_set.has(p_new_name));
+void AnimationPlayer::_animation_removed(const StringName &p_name, const StringName &p_library) {
+	StringName name = p_library == StringName() ? p_name : StringName(String(p_library) + "/" + String(p_name));
 
-	stop();
-	AnimationData ad = animation_set[p_name];
-	ad.name = p_new_name;
-	animation_set.erase(p_name);
-	animation_set[p_new_name] = ad;
+	if (!animation_set.has(name)) {
+		return; // No need to update because not the one from the library being used.
+	}
+	_animation_set_cache_update();
+
+	// Erase blends if needed
+	List<BlendKey> to_erase;
+	for (const KeyValue<BlendKey, float> &E : blend_times) {
+		BlendKey bk = E.key;
+		if (bk.from == name || bk.to == name) {
+			to_erase.push_back(bk);
+		}
+	}
+
+	while (to_erase.size()) {
+		blend_times.erase(to_erase.front()->get());
+		to_erase.pop_front();
+	}
+
+	update_configuration_warnings();
+}
 
+void AnimationPlayer::_rename_animation(const StringName &p_from_name, const StringName &p_to_name) {
+	// Rename autoplay or blends if needed.
 	List<BlendKey> to_erase;
 	Map<BlendKey, float> to_insert;
 	for (const KeyValue<BlendKey, float> &E : blend_times) {
 		BlendKey bk = E.key;
 		BlendKey new_bk = bk;
 		bool erase = false;
-		if (bk.from == p_name) {
-			new_bk.from = p_new_name;
+		if (bk.from == p_from_name) {
+			new_bk.from = p_to_name;
 			erase = true;
 		}
-		if (bk.to == p_name) {
-			new_bk.to = p_new_name;
+		if (bk.to == p_from_name) {
+			new_bk.to = p_to_name;
 			erase = true;
 		}
 
@@ -1239,12 +1302,184 @@ void AnimationPlayer::rename_animation(const StringName &p_name, const StringNam
 		to_insert.erase(to_insert.front());
 	}
 
-	if (autoplay == p_name) {
-		autoplay = p_new_name;
+	if (autoplay == p_from_name) {
+		autoplay = p_to_name;
 	}
+}
+
+void AnimationPlayer::_animation_renamed(const StringName &p_name, const StringName &p_to_name, const StringName &p_library) {
+	StringName from_name = p_library == StringName() ? p_name : StringName(String(p_library) + "/" + String(p_name));
+	StringName to_name = p_library == StringName() ? p_to_name : StringName(String(p_library) + "/" + String(p_to_name));
+
+	if (!animation_set.has(from_name)) {
+		return; // No need to update because not the one from the library being used.
+	}
+	_animation_set_cache_update();
+
+	_rename_animation(from_name, to_name);
+	update_configuration_warnings();
+}
+
+Error AnimationPlayer::add_animation_library(const StringName &p_name, const Ref<AnimationLibrary> &p_animation_library) {
+	ERR_FAIL_COND_V(p_animation_library.is_null(), ERR_INVALID_PARAMETER);
+#ifdef DEBUG_ENABLED
+	ERR_FAIL_COND_V_MSG(String(p_name).contains("/") || String(p_name).contains(":") || String(p_name).contains(",") || String(p_name).contains("["), ERR_INVALID_PARAMETER, "Invalid animation name: " + String(p_name) + ".");
+#endif
+
+	int insert_pos = 0;
+
+	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+		ERR_FAIL_COND_V_MSG(animation_libraries[i].name == p_name, ERR_ALREADY_EXISTS, "Can't add animation library twice with name: " + String(p_name));
+		ERR_FAIL_COND_V_MSG(animation_libraries[i].library == p_animation_library, ERR_ALREADY_EXISTS, "Can't add animation library twice (adding as '" + p_name.operator String() + "', exists as '" + animation_libraries[i].name.operator String() + "'.");
+
+		if (animation_libraries[i].name.operator String() >= p_name.operator String()) {
+			break;
+		}
+
+		insert_pos++;
+	}
+
+	AnimationLibraryData ald;
+	ald.name = p_name;
+	ald.library = p_animation_library;
+
+	animation_libraries.insert(insert_pos, ald);
+
+	ald.library->connect(SNAME("animation_added"), callable_mp(this, &AnimationPlayer::_animation_added), varray(p_name));
+	ald.library->connect(SNAME("animation_removed"), callable_mp(this, &AnimationPlayer::_animation_added), varray(p_name));
+	ald.library->connect(SNAME("animation_renamed"), callable_mp(this, &AnimationPlayer::_animation_renamed), varray(p_name));
+
+	_animation_set_cache_update();
+
+	notify_property_list_changed();
+
+	update_configuration_warnings();
+	return OK;
+}
+
+void AnimationPlayer::remove_animation_library(const StringName &p_name) {
+	int at_pos = -1;
+
+	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+		if (animation_libraries[i].name == p_name) {
+			at_pos = i;
+			break;
+		}
+	}
+
+	ERR_FAIL_COND(at_pos == -1);
+
+	animation_libraries[at_pos].library->disconnect(SNAME("animation_added"), callable_mp(this, &AnimationPlayer::_animation_added));
+	animation_libraries[at_pos].library->disconnect(SNAME("animation_removed"), callable_mp(this, &AnimationPlayer::_animation_added));
+	animation_libraries[at_pos].library->disconnect(SNAME("animation_renamed"), callable_mp(this, &AnimationPlayer::_animation_renamed));
+
+	stop();
+
+	for (const KeyValue<StringName, Ref<Animation>> &K : animation_libraries[at_pos].library->animations) {
+		_unref_anim(K.value);
+	}
+
+	animation_libraries.remove_at(at_pos);
+	_animation_set_cache_update();
 
-	clear_caches();
 	notify_property_list_changed();
+	update_configuration_warnings();
+}
+
+void AnimationPlayer::_ref_anim(const Ref<Animation> &p_anim) {
+	Ref<Animation>(p_anim)->connect(SceneStringNames::get_singleton()->tracks_changed, callable_mp(this, &AnimationPlayer::_animation_changed), varray(), CONNECT_REFERENCE_COUNTED);
+}
+
+void AnimationPlayer::_unref_anim(const Ref<Animation> &p_anim) {
+	Ref<Animation>(p_anim)->disconnect(SceneStringNames::get_singleton()->tracks_changed, callable_mp(this, &AnimationPlayer::_animation_changed));
+}
+
+void AnimationPlayer::rename_animation_library(const StringName &p_name, const StringName &p_new_name) {
+	if (p_name == p_new_name) {
+		return;
+	}
+#ifdef DEBUG_ENABLED
+	ERR_FAIL_COND_MSG(String(p_new_name).contains("/") || String(p_new_name).contains(":") || String(p_new_name).contains(",") || String(p_new_name).contains("["), "Invalid animation library name: " + String(p_new_name) + ".");
+#endif
+
+	bool found = false;
+	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+		ERR_FAIL_COND_MSG(animation_libraries[i].name == p_new_name, "Can't rename animation library to another existing name: " + String(p_new_name));
+		if (animation_libraries[i].name == p_name) {
+			found = true;
+			animation_libraries[i].name = p_new_name;
+			// rename connections
+			animation_libraries[i].library->disconnect(SNAME("animation_added"), callable_mp(this, &AnimationPlayer::_animation_added));
+			animation_libraries[i].library->disconnect(SNAME("animation_removed"), callable_mp(this, &AnimationPlayer::_animation_added));
+			animation_libraries[i].library->disconnect(SNAME("animation_renamed"), callable_mp(this, &AnimationPlayer::_animation_renamed));
+
+			animation_libraries[i].library->connect(SNAME("animation_added"), callable_mp(this, &AnimationPlayer::_animation_added), varray(p_new_name));
+			animation_libraries[i].library->connect(SNAME("animation_removed"), callable_mp(this, &AnimationPlayer::_animation_added), varray(p_new_name));
+			animation_libraries[i].library->connect(SNAME("animation_renamed"), callable_mp(this, &AnimationPlayer::_animation_renamed), varray(p_new_name));
+
+			for (const KeyValue<StringName, Ref<Animation>> &K : animation_libraries[i].library->animations) {
+				StringName old_name = p_name == StringName() ? K.key : StringName(String(p_name) + "/" + String(K.key));
+				StringName new_name = p_new_name == StringName() ? K.key : StringName(String(p_new_name) + "/" + String(K.key));
+				_rename_animation(old_name, new_name);
+			}
+		}
+	}
+
+	ERR_FAIL_COND(!found);
+
+	stop();
+
+	animation_libraries.sort(); // Must keep alphabetical order.
+
+	_animation_set_cache_update(); // Update cache.
+
+	notify_property_list_changed();
+}
+
+bool AnimationPlayer::has_animation_library(const StringName &p_name) const {
+	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+		if (animation_libraries[i].name == p_name) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+Ref<AnimationLibrary> AnimationPlayer::get_animation_library(const StringName &p_name) const {
+	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+		if (animation_libraries[i].name == p_name) {
+			return animation_libraries[i].library;
+		}
+	}
+	ERR_FAIL_V(Ref<AnimationLibrary>());
+}
+
+TypedArray<StringName> AnimationPlayer::_get_animation_library_list() const {
+	TypedArray<StringName> ret;
+	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+		ret.push_back(animation_libraries[i].name);
+	}
+	return ret;
+}
+
+void AnimationPlayer::get_animation_library_list(List<StringName> *p_libraries) const {
+	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+		p_libraries->push_back(animation_libraries[i].name);
+	}
+}
+
+TypedArray<String> AnimationPlayer::get_configuration_warnings() const {
+	TypedArray<String> warnings = Node::get_configuration_warnings();
+
+	for (uint32_t i = 0; i < animation_libraries.size(); i++) {
+		for (const KeyValue<StringName, Ref<Animation>> &K : animation_libraries[i].library->animations) {
+			if (animation_set.has(K.key) && animation_set[K.key].animation_library != animation_libraries[i].name) {
+				warnings.push_back(vformat(RTR("Animation '%s' in library '%s' is unused because another animation with the same name exists in library '%s'."), K.key, animation_libraries[i].name, animation_set[K.key].animation_library));
+			}
+		}
+	}
+	return warnings;
 }
 
 bool AnimationPlayer::has_animation(const StringName &p_name) const {
@@ -1585,7 +1820,16 @@ StringName AnimationPlayer::find_animation(const Ref<Animation> &p_animation) co
 		}
 	}
 
-	return "";
+	return StringName();
+}
+
+StringName AnimationPlayer::find_animation_library(const Ref<Animation> &p_animation) const {
+	for (const KeyValue<StringName, AnimationData> &E : animation_set) {
+		if (E.value.animation == p_animation) {
+			return E.value.animation_library;
+		}
+	}
+	return StringName();
 }
 
 void AnimationPlayer::set_autoplay(const String &p_name) {
@@ -1764,7 +2008,10 @@ Ref<AnimatedValuesBackup> AnimationPlayer::apply_reset(bool p_user_initiated) {
 
 	AnimationPlayer *aux_player = memnew(AnimationPlayer);
 	EditorNode::get_singleton()->add_child(aux_player);
-	aux_player->add_animation(SceneStringNames::get_singleton()->RESET, reset_anim);
+	Ref<AnimationLibrary> al;
+	al.instantiate();
+	al->add_animation(SceneStringNames::get_singleton()->RESET, reset_anim);
+	aux_player->add_animation_library("default", al);
 	aux_player->set_assigned_animation(SceneStringNames::get_singleton()->RESET);
 	// Forcing the use of the original root because the scene where original player belongs may be not the active one
 	Node *root = get_node(get_root());
@@ -1792,9 +2039,13 @@ bool AnimationPlayer::can_apply_reset() const {
 #endif // TOOLS_ENABLED
 
 void AnimationPlayer::_bind_methods() {
-	ClassDB::bind_method(D_METHOD("add_animation", "name", "animation"), &AnimationPlayer::add_animation);
-	ClassDB::bind_method(D_METHOD("remove_animation", "name"), &AnimationPlayer::remove_animation);
-	ClassDB::bind_method(D_METHOD("rename_animation", "name", "newname"), &AnimationPlayer::rename_animation);
+	ClassDB::bind_method(D_METHOD("add_animation_library", "name", "library"), &AnimationPlayer::add_animation_library);
+	ClassDB::bind_method(D_METHOD("remove_animation_library", "name"), &AnimationPlayer::remove_animation_library);
+	ClassDB::bind_method(D_METHOD("rename_animation_library", "name", "newname"), &AnimationPlayer::rename_animation_library);
+	ClassDB::bind_method(D_METHOD("has_animation_library", "name"), &AnimationPlayer::has_animation_library);
+	ClassDB::bind_method(D_METHOD("get_animation_library", "name"), &AnimationPlayer::get_animation_library);
+	ClassDB::bind_method(D_METHOD("get_animation_library_list"), &AnimationPlayer::_get_animation_library_list);
+
 	ClassDB::bind_method(D_METHOD("has_animation", "name"), &AnimationPlayer::has_animation);
 	ClassDB::bind_method(D_METHOD("get_animation", "name"), &AnimationPlayer::get_animation);
 	ClassDB::bind_method(D_METHOD("get_animation_list"), &AnimationPlayer::_get_animation_list);
@@ -1838,6 +2089,7 @@ void AnimationPlayer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_root"), &AnimationPlayer::get_root);
 
 	ClassDB::bind_method(D_METHOD("find_animation", "animation"), &AnimationPlayer::find_animation);
+	ClassDB::bind_method(D_METHOD("find_animation_library", "animation"), &AnimationPlayer::find_animation_library);
 
 	ClassDB::bind_method(D_METHOD("clear_caches"), &AnimationPlayer::clear_caches);
 
diff --git a/scene/animation/animation_player.h b/scene/animation/animation_player.h
index a68f6b9d5b..1d450175ad 100644
--- a/scene/animation/animation_player.h
+++ b/scene/animation/animation_player.h
@@ -36,6 +36,7 @@
 #include "scene/3d/node_3d.h"
 #include "scene/3d/skeleton_3d.h"
 #include "scene/resources/animation.h"
+#include "scene/resources/animation_library.h"
 
 #ifdef TOOLS_ENABLED
 class AnimatedValuesBackup : public RefCounted {
@@ -184,9 +185,20 @@ private:
 		StringName next;
 		Vector<TrackNodeCache *> node_cache;
 		Ref<Animation> animation;
+		StringName animation_library;
+		uint64_t last_update = 0;
 	};
 
 	Map<StringName, AnimationData> animation_set;
+
+	struct AnimationLibraryData {
+		StringName name;
+		Ref<AnimationLibrary> library;
+		bool operator<(const AnimationLibraryData &p_data) const { return name.operator String() < p_data.name.operator String(); }
+	};
+
+	LocalVector<AnimationLibraryData> animation_libraries;
+
 	struct BlendKey {
 		StringName from;
 		StringName to;
@@ -261,6 +273,15 @@ private:
 
 	bool playing = false;
 
+	uint64_t animation_set_update_pass = 1;
+	void _animation_set_cache_update();
+	void _animation_added(const StringName &p_name, const StringName &p_library);
+	void _animation_removed(const StringName &p_name, const StringName &p_library);
+	void _animation_renamed(const StringName &p_name, const StringName &p_to_name, const StringName &p_library);
+	void _rename_animation(const StringName &p_from_name, const StringName &p_to_name);
+
+	TypedArray<StringName> _get_animation_library_list() const;
+
 protected:
 	bool _set(const StringName &p_name, const Variant &p_value);
 	bool _get(const StringName &p_name, Variant &r_ret) const;
@@ -272,13 +293,18 @@ protected:
 
 public:
 	StringName find_animation(const Ref<Animation> &p_animation) const;
+	StringName find_animation_library(const Ref<Animation> &p_animation) const;
+
+	Error add_animation_library(const StringName &p_name, const Ref<AnimationLibrary> &p_animation_library);
+	void remove_animation_library(const StringName &p_name);
+	void rename_animation_library(const StringName &p_name, const StringName &p_new_name);
+	Ref<AnimationLibrary> get_animation_library(const StringName &p_name) const;
+	void get_animation_library_list(List<StringName> *p_animations) const;
+	bool has_animation_library(const StringName &p_name) const;
 
-	Error add_animation(const StringName &p_name, const Ref<Animation> &p_animation);
-	void remove_animation(const StringName &p_name);
-	void rename_animation(const StringName &p_name, const StringName &p_new_name);
-	bool has_animation(const StringName &p_name) const;
 	Ref<Animation> get_animation(const StringName &p_name) const;
 	void get_animation_list(List<StringName> *p_animations) const;
+	bool has_animation(const StringName &p_name) const;
 
 	void set_blend_time(const StringName &p_animation1, const StringName &p_animation2, float p_time);
 	float get_blend_time(const StringName &p_animation1, const StringName &p_animation2) const;
@@ -340,6 +366,8 @@ public:
 	bool can_apply_reset() const;
 #endif
 
+	TypedArray<String> get_configuration_warnings() const override;
+
 	AnimationPlayer();
 	~AnimationPlayer();
 };
diff --git a/scene/gui/option_button.cpp b/scene/gui/option_button.cpp
index 1e8a149e11..307696c44a 100644
--- a/scene/gui/option_button.cpp
+++ b/scene/gui/option_button.cpp
@@ -203,16 +203,18 @@ void OptionButton::pressed() {
 }
 
 void OptionButton::add_icon_item(const Ref<Texture2D> &p_icon, const String &p_label, int p_id) {
+	bool first_selectable = !has_selectable_items();
 	popup->add_icon_radio_check_item(p_icon, p_label, p_id);
-	if (popup->get_item_count() == 1) {
-		select(0);
+	if (first_selectable) {
+		select(get_item_count() - 1);
 	}
 }
 
 void OptionButton::add_item(const String &p_label, int p_id) {
+	bool first_selectable = !has_selectable_items();
 	popup->add_radio_check_item(p_label, p_id);
-	if (popup->get_item_count() == 1) {
-		select(0);
+	if (first_selectable) {
+		select(get_item_count() - 1);
 	}
 }
 
@@ -280,6 +282,9 @@ bool OptionButton::is_item_disabled(int p_idx) const {
 	return popup->is_item_disabled(p_idx);
 }
 
+bool OptionButton::is_item_separator(int p_idx) const {
+	return popup->is_item_separator(p_idx);
+}
 void OptionButton::set_item_count(int p_count) {
 	ERR_FAIL_COND(p_count < 0);
 
@@ -299,12 +304,37 @@ void OptionButton::set_item_count(int p_count) {
 	notify_property_list_changed();
 }
 
+bool OptionButton::has_selectable_items() const {
+	for (int i = 0; i < get_item_count(); i++) {
+		if (!is_item_disabled(i) && !is_item_separator(i)) {
+			return true;
+		}
+	}
+	return false;
+}
+int OptionButton::get_selectable_item(bool p_from_last) const {
+	if (!p_from_last) {
+		for (int i = 0; i < get_item_count(); i++) {
+			if (!is_item_disabled(i) && !is_item_separator(i)) {
+				return i;
+			}
+		}
+	} else {
+		for (int i = get_item_count() - 1; i >= 0; i++) {
+			if (!is_item_disabled(i) && !is_item_separator(i)) {
+				return i;
+			}
+		}
+	}
+	return -1;
+}
+
 int OptionButton::get_item_count() const {
 	return popup->get_item_count();
 }
 
-void OptionButton::add_separator() {
-	popup->add_separator();
+void OptionButton::add_separator(const String &p_text) {
+	popup->add_separator(p_text);
 }
 
 void OptionButton::clear() {
@@ -407,7 +437,8 @@ void OptionButton::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_item_metadata", "idx"), &OptionButton::get_item_metadata);
 	ClassDB::bind_method(D_METHOD("get_item_tooltip", "idx"), &OptionButton::get_item_tooltip);
 	ClassDB::bind_method(D_METHOD("is_item_disabled", "idx"), &OptionButton::is_item_disabled);
-	ClassDB::bind_method(D_METHOD("add_separator"), &OptionButton::add_separator);
+	ClassDB::bind_method(D_METHOD("is_item_separator", "idx"), &OptionButton::is_item_separator);
+	ClassDB::bind_method(D_METHOD("add_separator", "text"), &OptionButton::add_separator, DEFVAL(String()));
 	ClassDB::bind_method(D_METHOD("clear"), &OptionButton::clear);
 	ClassDB::bind_method(D_METHOD("select", "idx"), &OptionButton::select);
 	ClassDB::bind_method(D_METHOD("get_selected"), &OptionButton::get_selected);
@@ -420,6 +451,8 @@ void OptionButton::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("set_item_count", "count"), &OptionButton::set_item_count);
 	ClassDB::bind_method(D_METHOD("get_item_count"), &OptionButton::get_item_count);
+	ClassDB::bind_method(D_METHOD("has_selectable_items"), &OptionButton::has_selectable_items);
+	ClassDB::bind_method(D_METHOD("get_selectable_item", "from_last"), &OptionButton::get_selectable_item, DEFVAL(false));
 
 	// "selected" property must come after "item_count", otherwise GH-10213 occurs.
 	ADD_ARRAY_COUNT("Items", "item_count", "set_item_count", "get_item_count", "popup/item_");
diff --git a/scene/gui/option_button.h b/scene/gui/option_button.h
index 921b76c52a..7896132626 100644
--- a/scene/gui/option_button.h
+++ b/scene/gui/option_button.h
@@ -77,12 +77,16 @@ public:
 	int get_item_index(int p_id) const;
 	Variant get_item_metadata(int p_idx) const;
 	bool is_item_disabled(int p_idx) const;
+	bool is_item_separator(int p_idx) const;
 	String get_item_tooltip(int p_idx) const;
 
+	bool has_selectable_items() const;
+	int get_selectable_item(bool p_from_last = false) const;
+
 	void set_item_count(int p_count);
 	int get_item_count() const;
 
-	void add_separator();
+	void add_separator(const String &p_text = "");
 
 	void clear();
 
diff --git a/scene/gui/tree.cpp b/scene/gui/tree.cpp
index ccd24ed2cf..24cd485e1b 100644
--- a/scene/gui/tree.cpp
+++ b/scene/gui/tree.cpp
@@ -101,6 +101,7 @@ void TreeItem::_change_tree(Tree *p_tree) {
 
 		if (tree->popup_edited_item == this) {
 			tree->popup_edited_item = nullptr;
+			tree->popup_pressing_edited_item = nullptr;
 			tree->pressing_for_editor = false;
 		}
 
@@ -2670,8 +2671,8 @@ int Tree::propagate_mouse_event(const Point2i &p_pos, int x_ofs, int y_ofs, int
 		}
 
 		click_handled = true;
-		popup_edited_item = p_item;
-		popup_edited_item_col = col;
+		popup_pressing_edited_item = p_item;
+		popup_pressing_edited_item_column = col;
 
 		pressing_item_rect = Rect2(get_global_position() + Point2i(col_ofs, _get_title_button_height() + y_ofs) - cache.offset, Size2(col_width, item_h));
 		pressing_for_editor_text = editor_text;
@@ -3206,10 +3207,16 @@ void Tree::gui_input(const Ref<InputEvent> &p_event) {
 			update();
 		}
 
-		if (pressing_for_editor && popup_edited_item && (popup_edited_item->get_cell_mode(popup_edited_item_col) == TreeItem::CELL_MODE_RANGE)) {
-			//range drag
+		if (pressing_for_editor && popup_pressing_edited_item && (popup_pressing_edited_item->get_cell_mode(popup_pressing_edited_item_column) == TreeItem::CELL_MODE_RANGE)) {
+			/* This needs to happen now, because the popup can be closed when pressing another item, and must remain the popup edited item until it actually closes */
+			popup_edited_item = popup_pressing_edited_item;
+			popup_edited_item_col = popup_pressing_edited_item_column;
+
+			popup_pressing_edited_item = nullptr;
+			popup_pressing_edited_item_column = -1;
 
 			if (!range_drag_enabled) {
+				//range drag
 				Vector2 cpos = mm->get_position();
 				if (rtl) {
 					cpos.x = get_size().width - cpos.x;
@@ -3994,6 +4001,7 @@ void Tree::clear() {
 	selected_item = nullptr;
 	edited_item = nullptr;
 	popup_edited_item = nullptr;
+	popup_pressing_edited_item = nullptr;
 
 	update();
 };
@@ -4309,12 +4317,16 @@ int Tree::get_pressed_button() const {
 	return pressed_button;
 }
 
-Rect2 Tree::get_item_rect(TreeItem *p_item, int p_column) const {
+Rect2 Tree::get_item_rect(TreeItem *p_item, int p_column, int p_button) const {
 	ERR_FAIL_NULL_V(p_item, Rect2());
 	ERR_FAIL_COND_V(p_item->tree != this, Rect2());
 	if (p_column != -1) {
 		ERR_FAIL_INDEX_V(p_column, columns.size(), Rect2());
 	}
+	if (p_button != -1) {
+		ERR_FAIL_COND_V(p_column == -1, Rect2()); // pass a column if you want to pass a button
+		ERR_FAIL_INDEX_V(p_button, p_item->cells[p_column].buttons.size(), Rect2());
+	}
 
 	int ofs = get_item_offset(p_item);
 	int height = compute_item_height(p_item);
@@ -4332,6 +4344,19 @@ Rect2 Tree::get_item_rect(TreeItem *p_item, int p_column) const {
 		}
 		r.position.x = accum;
 		r.size.x = get_column_width(p_column);
+		if (p_button != -1) {
+			const TreeItem::Cell &c = p_item->cells[p_column];
+			Vector2 ofst = Vector2(r.position.x + r.size.x, r.position.y);
+			for (int j = c.buttons.size() - 1; j >= 0; j--) {
+				Ref<Texture2D> b = c.buttons[j].texture;
+				Size2 size = b->get_size() + cache.button_pressed->get_minimum_size();
+				ofst.x -= size.x;
+
+				if (j == p_button) {
+					return Rect2(ofst, size);
+				}
+			}
+		}
 	}
 
 	return r;
@@ -4870,7 +4895,7 @@ void Tree::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_edited_column"), &Tree::get_edited_column);
 	ClassDB::bind_method(D_METHOD("edit_selected"), &Tree::edit_selected);
 	ClassDB::bind_method(D_METHOD("get_custom_popup_rect"), &Tree::get_custom_popup_rect);
-	ClassDB::bind_method(D_METHOD("get_item_area_rect", "item", "column"), &Tree::get_item_rect, DEFVAL(-1));
+	ClassDB::bind_method(D_METHOD("get_item_area_rect", "item", "column", "button_index"), &Tree::get_item_rect, DEFVAL(-1), DEFVAL(-1));
 	ClassDB::bind_method(D_METHOD("get_item_at_position", "position"), &Tree::get_item_at_position);
 	ClassDB::bind_method(D_METHOD("get_column_at_position", "position"), &Tree::get_column_at_position);
 	ClassDB::bind_method(D_METHOD("get_drop_section_at_position", "position"), &Tree::get_drop_section_at_position);
diff --git a/scene/gui/tree.h b/scene/gui/tree.h
index 74ad4f94b8..b704495444 100644
--- a/scene/gui/tree.h
+++ b/scene/gui/tree.h
@@ -379,6 +379,9 @@ private:
 	TreeItem *selected_item = nullptr;
 	TreeItem *edited_item = nullptr;
 
+	TreeItem *popup_pressing_edited_item = nullptr; // Candidate.
+	int popup_pressing_edited_item_column = -1;
+
 	TreeItem *drop_mode_over = nullptr;
 	int drop_mode_section = 0;
 
@@ -673,7 +676,7 @@ public:
 	Rect2 get_custom_popup_rect() const;
 
 	int get_item_offset(TreeItem *p_item) const;
-	Rect2 get_item_rect(TreeItem *p_item, int p_column = -1) const;
+	Rect2 get_item_rect(TreeItem *p_item, int p_column = -1, int p_button = -1) const;
 	bool edit_selected();
 	bool is_editing();
 
diff --git a/scene/register_scene_types.cpp b/scene/register_scene_types.cpp
index 5b56d9b11e..127e734e6c 100644
--- a/scene/register_scene_types.cpp
+++ b/scene/register_scene_types.cpp
@@ -139,6 +139,7 @@
 #include "scene/multiplayer/scene_cache_interface.h"
 #include "scene/multiplayer/scene_replication_interface.h"
 #include "scene/multiplayer/scene_rpc_interface.h"
+#include "scene/resources/animation_library.h"
 #include "scene/resources/audio_stream_sample.h"
 #include "scene/resources/bit_map.h"
 #include "scene/resources/box_shape_3d.h"
@@ -834,6 +835,7 @@ void register_scene_types() {
 	GDREGISTER_CLASS(CompressedTexture2DArray);
 
 	GDREGISTER_CLASS(Animation);
+	GDREGISTER_CLASS(AnimationLibrary);
 	GDREGISTER_CLASS(FontData);
 	GDREGISTER_CLASS(Font);
 	GDREGISTER_CLASS(Curve);
diff --git a/scene/resources/animation_library.cpp b/scene/resources/animation_library.cpp
new file mode 100644
index 0000000000..f7b8c6a648
--- /dev/null
+++ b/scene/resources/animation_library.cpp
@@ -0,0 +1,134 @@
+/*************************************************************************/
+/*  animation_library.cpp                                                */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "animation_library.h"
+
+Error AnimationLibrary::add_animation(const StringName &p_name, const Ref<Animation> &p_animation) {
+	ERR_FAIL_COND_V_MSG(String(p_name).contains("/") || String(p_name).contains(":") || String(p_name).contains(",") || String(p_name).contains("["), ERR_INVALID_PARAMETER, "Invalid animation name: " + String(p_name) + ".");
+	ERR_FAIL_COND_V(p_animation.is_null(), ERR_INVALID_PARAMETER);
+
+	if (animations.has(p_name)) {
+		animations.erase(p_name);
+		emit_signal(SNAME("animation_removed"), p_name);
+	}
+
+	animations.insert(p_name, p_animation);
+	emit_signal(SNAME("animation_added"), p_name);
+	notify_property_list_changed();
+	return OK;
+}
+
+void AnimationLibrary::remove_animation(const StringName &p_name) {
+	ERR_FAIL_COND(!animations.has(p_name));
+
+	animations.erase(p_name);
+	emit_signal(SNAME("animation_removed"), p_name);
+	notify_property_list_changed();
+}
+
+void AnimationLibrary::rename_animation(const StringName &p_name, const StringName &p_new_name) {
+	ERR_FAIL_COND(!animations.has(p_name));
+	ERR_FAIL_COND_MSG(String(p_name).contains("/") || String(p_name).contains(":") || String(p_name).contains(",") || String(p_name).contains("["), "Invalid animation name: " + String(p_name) + ".");
+	ERR_FAIL_COND(animations.has(p_new_name));
+
+	animations.insert(p_new_name, animations[p_name]);
+	animations.erase(p_name);
+	emit_signal(SNAME("animation_renamed"), p_name, p_new_name);
+}
+
+bool AnimationLibrary::has_animation(const StringName &p_name) const {
+	return animations.has(p_name);
+}
+
+Ref<Animation> AnimationLibrary::get_animation(const StringName &p_name) const {
+	ERR_FAIL_COND_V(!animations.has(p_name), Ref<Animation>());
+
+	return animations[p_name];
+}
+
+TypedArray<StringName> AnimationLibrary::_get_animation_list() const {
+	TypedArray<StringName> ret;
+	List<StringName> names;
+	get_animation_list(&names);
+	for (const StringName &K : names) {
+		ret.push_back(K);
+	}
+	return ret;
+}
+
+void AnimationLibrary::get_animation_list(List<StringName> *p_animations) const {
+	List<StringName> anims;
+
+	for (const KeyValue<StringName, Ref<Animation>> &E : animations) {
+		anims.push_back(E.key);
+	}
+
+	anims.sort_custom<StringName::AlphCompare>();
+
+	for (const StringName &E : anims) {
+		p_animations->push_back(E);
+	}
+}
+
+void AnimationLibrary::_set_data(const Dictionary &p_data) {
+	animations.clear();
+	List<Variant> keys;
+	p_data.get_key_list(&keys);
+	for (const Variant &K : keys) {
+		add_animation(K, p_data[K]);
+	}
+}
+
+Dictionary AnimationLibrary::_get_data() const {
+	Dictionary ret;
+	for (const KeyValue<StringName, Ref<Animation>> &K : animations) {
+		ret[K.key] = K.value;
+	}
+	return ret;
+}
+
+void AnimationLibrary::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("add_animation", "name", "animation"), &AnimationLibrary::add_animation);
+	ClassDB::bind_method(D_METHOD("remove_animation", "name"), &AnimationLibrary::remove_animation);
+	ClassDB::bind_method(D_METHOD("rename_animation", "name", "newname"), &AnimationLibrary::rename_animation);
+	ClassDB::bind_method(D_METHOD("has_animation", "name"), &AnimationLibrary::has_animation);
+	ClassDB::bind_method(D_METHOD("get_animation", "name"), &AnimationLibrary::get_animation);
+	ClassDB::bind_method(D_METHOD("get_animation_list"), &AnimationLibrary::_get_animation_list);
+
+	ClassDB::bind_method(D_METHOD("_set_data", "data"), &AnimationLibrary::_set_data);
+	ClassDB::bind_method(D_METHOD("_get_data"), &AnimationLibrary::_get_data);
+
+	ADD_PROPERTY(PropertyInfo(Variant::DICTIONARY, "_data", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR), "_set_data", "_get_data");
+	ADD_SIGNAL(MethodInfo("animation_added", PropertyInfo(Variant::OBJECT, "name", PROPERTY_HINT_RESOURCE_TYPE, "Animation")));
+	ADD_SIGNAL(MethodInfo("animation_removed", PropertyInfo(Variant::OBJECT, "name", PROPERTY_HINT_RESOURCE_TYPE, "Animation")));
+	ADD_SIGNAL(MethodInfo("animation_renamed", PropertyInfo(Variant::OBJECT, "name", PROPERTY_HINT_RESOURCE_TYPE, "Animation"), PropertyInfo(Variant::OBJECT, "to_name", PROPERTY_HINT_RESOURCE_TYPE, "Animation")));
+}
+AnimationLibrary::AnimationLibrary() {
+}
diff --git a/scene/resources/animation_library.h b/scene/resources/animation_library.h
new file mode 100644
index 0000000000..69ac5a97d2
--- /dev/null
+++ b/scene/resources/animation_library.h
@@ -0,0 +1,62 @@
+/*************************************************************************/
+/*  animation_library.h                                                  */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef ANIMATION_LIBRARY_H
+#define ANIMATION_LIBRARY_H
+
+#include "core/variant/typed_array.h"
+#include "scene/resources/animation.h"
+
+class AnimationLibrary : public Resource {
+	GDCLASS(AnimationLibrary, Resource)
+
+	void _set_data(const Dictionary &p_data);
+	Dictionary _get_data() const;
+
+	TypedArray<StringName> _get_animation_list() const;
+
+	friend class AnimationPlayer; //for faster access
+	Map<StringName, Ref<Animation>> animations;
+
+protected:
+	static void _bind_methods();
+
+public:
+	Error add_animation(const StringName &p_name, const Ref<Animation> &p_animation);
+	void remove_animation(const StringName &p_name);
+	void rename_animation(const StringName &p_name, const StringName &p_new_name);
+	bool has_animation(const StringName &p_name) const;
+	Ref<Animation> get_animation(const StringName &p_name) const;
+	void get_animation_list(List<StringName> *p_animations) const;
+
+	AnimationLibrary();
+};
+
+#endif // ANIMATIONLIBRARY_H