Any game. It’s a remote desktop app, basically. If it’s a steam game, it will come with a default phone touchscreen gamepad set up and usually there are also official and community layouts you can use. The layouts are… not as good as you might like, and I am frequently having issues with my custom ones disappearing or not loading. But it’s not the worst thing ever and I can play modded skyrim on my phone at work.

Non-steam games can be added to the steam library and you can manage their controller schemes the same way- sometimes they will even have community layouts available also. MMV with non-steam games. For example, Valorant won’t recognize my mouse click on my phone. And certain apps apparently force you into a “local input only” mode and might kinda break your setup until you play around with it a bit (don’t go into task manager lol).

But yes, you can also easily connect a bluetooth controller to your phone and any game that uses a controller works great.