So many, it’s really impressive. Vampire Survivors to Elden Ring (with coop mod and Discord running in the background on SD), to No Man’s Sky, to Diablo 4 (through installed battle.net added to Steam as a Non-Steam game on the SD) all run great.
Also, if you have a good pc you can run the game there and stream it to the SD, extends run time on battery by quite a lot.
I played it start to finish on my deck using the co-op mod to play 2 player with my brother (who lives out of state). I also ran discord in the background on the deck, using headphones and the deck’s mic. Didn’t have any problems at all, super fun.