Right now, a kind of weird one: the Bridget MX, from SGF Devices. It's a 3D printed, all-button controller for fighting games. They don't make that specific model now (it was a very early one), but this is the closest to it: https://sgfdevices.com/products/bridget-pe

At first I thought that not having a joystick would make games kind of boring. Like, too practical, not enjoyable. But no, it's actually fun. Kind of like tapping out notes on a piano. It uses low-profile mechanical keyboard switches, and I have some stiffer, clickier switches on the way right now.

It's meant for fighting games (Street Fighter, etc.), but I've used it for some 2D platformers and it worked great for those, too.

A non-3D-printed, less cheapo one would probably be even more fun to use, but I think I'll stick with this one for now.