With the release of Valve's handheld PC just around the corner, Valve has finally released a tool to let users check how much of their Steam library will work on the Steam deck. Games are broken down into four categories for Steam Deck compatibility: Verified, meaning it works completely as intended; Playable, meaning it may take some extra work or configuration but can be played; Unsupported, meaning it won't work at all; and Untested, which simply means it hasn't been tested yet.
Remember that Valve and the games' devs can still work on better compatibility over time, so games which aren't supported right now, might(or might not) be supported later.
absolutely heartbreaking that TF2 isn't even on their list of fully-compatible games. I know it's unoptimized but goddamn they couldn't even update the game for a controller UI?