Depends on your needs really. I’m a big fan of the Morningstar stuff and @HazBeen is selling the excellent MC6 I sold him when I upgraded to the bigger MC8. If you wanted something with 12 buttons for the twelve chromatic pitches then a Macmillan 12 step or something might be better. Or some kind of midi organ foot pedal. I’d honestly suggest starting with the MC6 or smaller MC3 though.