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 ac…
If you're on Linux, Gromit-MPX is a great companion app to annotate anything on your desktop. https://github.com/bk138/gromit-mpx