@fluffy

> 2. game pads

Probably your best bet. The X11 joystick driver (originally designed as an accessibility system) would get you what you want, more or less, probably; you can map it to mouse/keyboard events. Like, attached is what I am using for the DevTerm.

If that kind of solution works for you, then you can grab a Wiimote. Should have enough buttons, maybe you can figure out how to map gestures, I don't know. Otherwise a PS3/PS4 controller definitely does, but I think a Wiimote is one-handed, right, and enough buttons.
10-joystick-mouse.conf