Titan Quest is an old favourite of mine, and I bought it Early Access some time ago hoping that it might run on Steamdeck. It very much does not.
It's coming out of Early Access in January 2027:
Luckily, it does run on Steam Machine, and I just got mine and set it up this weekend.
I've only played a little bit, with keyboard and mouse as control. I made a Storm (Lightning + Cold Magic) + Spirit (aka Necromancer) character which got released in August:
It's a pretty gorgeous game, and runs well on Steam Machine. I made it run at 1920x1080 and left the settings at Auto1.
For those that don't know it, it's an action RPG, and it's all about loot -- Diablo, Grim Dawn, Path of Exile are similar.
I did also briefly play Pass the Fear a "roguelite bullet-hell shooter" just to test the steam controller š