TBH I play games very little these days. Partly because my ancient hardware
doesn't support many games, and partly because if I'm going to use a computer
to explore a virtual world, interact with characters, and find surprises and
excitement, there's no better multi-player game than The Internet ;) I kept
some notes on some of the libre games I have tested. I probably spent the
most time on FreeDroid (loved ParaDroid on the C64 back in the 80s!), BOS
Wars, 0AD, and the Balderdash clone (can't remember what it was called and
it's not in my notes):
https://www.coactivate.org/projects/disintermedia/libre-games
I also keep some general notes on libre game development here:
https://www.coactivate.org/projects/disintermedia/libre-game-development