Hi all, I found the Research section on the jam page really interesting, so I did a little research myself and thought I'd share some of my findings (but talking to a person with a tremor disability would certainly be more accurate)!
1. Tremors can also cause accidental presses of adjacent keys, so it might be good to choose non-adjacent controls. (source)
2. For essential tremors, head shakes can also occur, so it might be good to keep relevant information on screen so the player won't miss it. (source)
3. Voice controls are also an option (if your engine supports it)! (source)