My current HotRod SE panel has 7 buttons per player, and I don't think I've ever used more than 3 for any game I've ever played on it for the last 12 years. I'm building a new CP and cramming a lot of controls into a 2-player panel, so I'm trying to hit the sweet spot for player buttons. I did just add NES and SNES to MAME in the cab, but I'm still not using more than a couple of buttons for the games I'm playing. I'm only planning to run MAME, Model 3, NES, and SNES for sure, and might add Dolphin and ePSXe later.
Is there a list somewhere that lists all games by the number of buttons it uses? If not, seems like that would be an extra resource to start.