Everyone probably knows that Sega Genesis Game pads work on Amigas and that they are available new at some of the game trading stores like GameStop. I've collected maybe a dozen of these. Usually, because Sega is different, only 1 fire button works, but it's still a usable joypad.
Whats new to me is that a very simple modification turns these into fully functional 6-button joypads. It was spelled out several years ago in the docs that come with ADoom, which was just re-released on Aminet. I did this last night. You simply swap the Vdd (+5 volts) and Sel wires inside the controller and connect a 470 ohm resister across these same 2 wires.
Of course, most games won't use all 6 buttons. But, it's nice to make these excellent controllers completely Amiga specific and compliant. Even the rapid fire functions work! These are better than the CD32 joypad.