At Chasing Amp Tone we put up a list of one knob tone controls. It has some standards, such as the Tweed tone control that was in a ton of old Fender amps and some more obscure ones.
It’s fun stuff to experiment with when building amps and wanting to do something a bit different. Besides the tone controls, there are mid and bass controls too so you can play mix and match and come up with a whole “tone stack”.
Check out the list here.