Steam has a list of games that are "Controller Friendly". I mean the Library view in Steam client, next to "All Games" list. On your Steam Deck it lists games that are verified for Steam Deck, but on PC client it lists games that are Controller friendly in general.
You can create a custom Collection for that too, a list that is available on all systems you log in. Go to "All Games" view, click "Fliter" (or X button), scroll down to "Hardware support" and enable filter "Full Controller Support". Scroll down and click "Save as Dynamic Collection". Name it and save it. Now this is a dymanic collection, which means it will automatically expand with new added games that fit this criteria. I would say all games from this list should fit your requirement and use case of being playable with a gamepad.