We developed this plugin internally for The Gateway of Realities Blender pipeline, and it is made to streamline exporting and selecting animations for our complex multi-armature rigs.

Actions are available in a always-visible list inspired by Akeytsu and every action can now have it's own frame-range (which can be automatically set).
All of this significantly speeds up workflow when you need to constantly jump between different animations.

For export the plugin has support of Unreal Engine 4 - tailored *.FBX format, and Second Life *.DAE (meshes) and *.ANIM (internal SL format) export options.

If you are interested in modding anything that we produced, usage of this tool is strongly recommended. Upon activation of the plugin the interface is located in the active tool tab of the properties editor.

The plugin is a work-in-progress and has no documentation yet (though it's not difficult to figure out).
However if you are modding the avatars, and have questions how to use the tool, feel free to ask Salireths on our Discord server or on Twitter.

Get on GitHub repository