I was just exploring trying to find this myself and very luckily stumbled upon it! go to window → Asset details and you’ll find an array of compatible skeletons.
Speaking of hidden gems that are easily missed, you will want to see the retarget options found by pressing “show retargeting options” after pressing the cog in the "skeleton tree " window!! You will certainly want to adjust those settings if you’re playing with different proportioned skeletons.
See this page for the correct settings and more info: Animation Retargeting | Unreal Engine Documentation
Epic if you’re listening please make these settings easier to find! And thank you for this greatly needed and appreciated feature!