Action Commander is a Blender add-on from TinkerBoi built around managing the many actions that pile up in a blend file. Its Multiple Action Management panel gathers actions in one place, so you avoid moving between separate sections. The core function is animation switching: the frame range adjusts when you switch action, and because actions are stored on the object itself, the list shows only the actions added to that object.
The add-on also handles FBX work. It can import FBX actions without their mesh or armature by wrapping Blender's internal Import FBX and cleaning up unnecessary data, with the option to load actions onto relevant objects. This suits bringing multiple Mixamo animations into a file without the extra geometry. An experimental export sends multiple actions from your list into single or multiple FBX files.
Shadow Rig Support lets you bake multiple actions from a control rig to a shadow rig, while the Action Bin lists every action in the file to help manage inactive or unwanted ones. Documentation is available, and bugs can be reported through the BlenderBoi Addon Support Discord.