

They don’t sell it anymore, but I use this super cheap tablet one, which only cost me $6.88.
It’s about the exact same length as the deck, and it has a flip out tablet stand that perfectly supports the steam deck.
I’m sure it’s not as nice as a lot of the keyboards mentioned in this thread, but it’s been perfect for me.
Here’s the installation instructions, although the build instructions are not going to work on Steam Deck by default due to it’s locked file system. I’ll probably try it on my desktop later and see if I can get it to work.
Ideally I think this project could later be installed through a decky plugin, similar to decky framegen.