The GP2040 firmware is extremely popular for its low latency, decent compatibility, SOCD cleaning, and more—especially if we’re talking about the GP2040-CE variant.
The Bishop|Select Opal is a more affordable version of the Maestro, and it's ergonomic—but not too ergonomic in a way that's unfamiliar.
The R10-Pro is an arcade stick with a trackball and spinner. You can also buy the R9 with just a spinner and the R10 with just a trackball.
The FightBox A10's silent Crown buttons allow you to perform at a high level without giving away your button presses to your nearby opponent.
Consider the Yume Tanuki if you'd like a small leverless controller that still has some decent height to it.
The X-Move is a sequel to Haute42's modular controller that was nominated for an Evo award, and you can move some of its modules sideways.
The Rushbox Click has the most insane layout yet, and it could be the first 22 button leverless controller.
The R8-SF2's Happ joystick and buttons in a straight layout let you play games like SF2 like how they were played decades ago in the States.
In its outrageous layout, the KBHX-01 MAX+ has 18 keys—most notably including four spacebars with enough surface area for comfy thumb presses.