Don't be shy to try out games that are specifically flagged as "unsupported". I have three of these that run just fine and one of them was flagged for verified later on.
Sunset Overdrive for instance is a case that's not supported, but run fine after an initial error message that could be ignored and it started and run anyway just fine.
Proton really does its wonders. Try out the experimental build under the compatibility settings if the standard version fails to run a game.
I’m going to go through my full library a lot more. Excited at the possibilities of this thing, and I’m glad it arrived shortly before we go on vacation!