Left handed trackball (Elecom). Sits to the left of my Moonlander while my vertical mouse sits to the right. Not only is it convenient, as an old school Diablo player I get to tell people I duel wield.
I also have a cheap X-Pen graphics tablet that I use for ‘white boarding’ on zoom calls.
Almost forgot I also have a usb wireless numpad that I pair with a usb hid remapped on a pi zero to make hot keys for frequent actions.