Another unconventional idea for the strap color for a gold Constellation watch (an early honeycomb 2648 here). Works great in summer and turns a dress watch into an eye-catcher (💃🕺)
I think there's already been many excellent suggestions, I'll just add that using ai could be incredibly helpful here. It can generate images of your watch on all sorts of different straps to give you an idea of what it'd look like