What are some niche things can could do/install/play on the steam deck that most people wouldn’t really do or think about doing?

I will say that the support for some of these “less used” games is very difficult to get running for someone who hasn’t used Linux before and controls will be tough depending on the game.
Getting OSRS with runelite was difficult but nice once i got it working. You need to get Wine to run the Jagex launcher then install Runelite separately. Don’t ask me how as I hardly remember how I did it myself lol

Also I haven’t tried this but getting Flash games would be dope. I don’t think I’ve seen anyone try it yet, but I’m sure someone has.

Also anybody know any casual games can play randomly on public transit and don’t have to sit down and play.

Celeste, Doom 1993, webfishing single player.