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.
To Live Is to Play is a store that sells this slim arcade stick compatible with Sanwa JLF PCB switches, including an adjustable shaft height.
The Furaipan by Akekon Dojo is essentially a frying pan with Sanwa buttons. Other options include a Sanwa lever edition.
The Alpenmeister TE's Hall effect switches allow you to adjust the button sensitivity, and there are also D-pad buttons near the aux buttons.
After the C16's immense success, Haute42 pleasantly surprised the FGC with the C16 Orange, which also upgrades the performance.
The Backdoor is the preassembled edition of Fruit Factory's Harvest enclosure, and you can order it with or without a joystick.
The Haute42 C-AS is a slim fightstick that lets you pick the joystick gate and button travel. It has optional analog sticks too.
Rushbox layouts are unique, and the Rushbox Mini gives you access to such a layout while remaining portable.
The Haute42 E16 is awesome for having a mirrored layout for left handed players, but if you're right handed, the E14A is a solid pick.