8BitDo says its controllers are now compatible with Steam/SteamOS. The announcement specifically mentions three models and advises users to update their controllers and Steam client to the latest version.
The SN30 is about as close as you can get to that, I think. I have two, and use them for everything. They’re basically SNES controllers with analog sticks. No paddles or other macro buttons. Just ABXY, dpad, start, select, shoulders, triggers and sticks.
They do also make the Micro, but that might be too tiny even for a child. Dpad and face buttons only.
The SN30 is about as close as you can get to that, I think. I have two, and use them for everything. They’re basically SNES controllers with analog sticks. No paddles or other macro buttons. Just ABXY, dpad, start, select, shoulders, triggers and sticks.
They do also make the Micro, but that might be too tiny even for a child. Dpad and face buttons only.