In case you don't own a Steam Deck and would like to see how much of your library would run on Linux:
1. Go to your library
2. Click the filter button
3. Under "hardware support" you'll see a dropdown "Steam Deck" with 4 options, here's some explanation what they mean:
Verified - Means this game 100% works on Linux (and Deck), which is verified by Valve
Playable - Means this game works on Linux (and Deck) but it might have some tiny issues (e.g. font size)
Untested - Might work, but not tested
So to check if your games would run pretty nicely either filter on "Verified" games or "Verified or playable" games and it filters out everything which will or might not run at all.
You'll be surprised how much games can run on Linux these days -- thanks to the massive effort Valve puts in Proton and some devs (including Valve) publishing native Linux builds of their games on Steam, and even things you might not even consider at all like Skyrim or Oblivion with all your favorite mods (!)
Also in some / many cases even "unsupported" games work out of the box or needs only minimal tweaking. AFAIK most of the issues are with online competitive games which uses anti-cheat.
To be fair, the Steam Deck support level is a bit arbitrary and some Verified games may work worse than some Untested games.
The only game that I had an issue with is The Unfinished Swan which I bought on Steam after having enjoyed playing it on a PS3 (good enough to buy twice). I couldn't get it to work initially with it just going to a blank screen (not the game itself which ironically does start with an all white screen) no matter my tinkering with Proton versions. However, tried it again a few months ago and it worked perfectly with default settings.
1. Go to your library
2. Click the filter button
3. Under "hardware support" you'll see a dropdown "Steam Deck" with 4 options, here's some explanation what they mean:
Verified - Means this game 100% works on Linux (and Deck), which is verified by Valve
Playable - Means this game works on Linux (and Deck) but it might have some tiny issues (e.g. font size)
Untested - Might work, but not tested
So to check if your games would run pretty nicely either filter on "Verified" games or "Verified or playable" games and it filters out everything which will or might not run at all.
You'll be surprised how much games can run on Linux these days -- thanks to the massive effort Valve puts in Proton and some devs (including Valve) publishing native Linux builds of their games on Steam, and even things you might not even consider at all like Skyrim or Oblivion with all your favorite mods (!)