Hi, there's a free (with bonus paid features) AI assisted animating tool called Cascadeur. Unfortunately it doesn't have much documentation other than few rather simple videos.

The link to their site: https://cascadeur.com/

On youtube you can input "cascadeur" and you'll see some videos. On these videos the tool looks really great but on practice it's very hard to use. And more important - there is no explanation how to edit existing animations. If you try to do something with loaded animation on certain keyframe then it'll forget that there's an animation and reset pose to default and only then apply changes to bone(s).

Since OpenGameArt is used by game devs and artists, may be some of you used this tool and have some insight? And if not, then this post will at least serve as free ad for the creators of this tool as AI role in animating looks very promising for people who don't have skills/time/money for high quality animations. I found this tool randomly by reading some reddit post and never even seen/heard about it anywhere before.