Programmed BASIC games on my TI-99/4A. Moved to programming on the C64 in BASIC and 6502. Went back and learned some TMS-9900 on the TI. Then went on to program in just about any high-level language I could get my damned hands on. Never programmed on the Amiga, though I really want to -- just need time.
I loved my 1351 mouse. Had one before I got GEOS, and even wrote some programs to use it. Tried to make it work with my TI with limited success in joystick mode. Although today I find I can get a lot more done and more quickly in a CLI or shell, provided the right commands exist.
Keyboard shortcuts? Just about every punctuation on the TI was a FCTN key. Not sure if that counts. Then there are all the C= key shortcuts in GEOS, Amiga key shortcuts, and so on.