The platform that an arcade controller works on may be a lead factor in your decision regarding whether or not to buy that controller.
The MPress Nano is a mini version of the critically acclaimed MPress and part of the Hit Box licensing program.
The Arashi by SaveYourGames can be ordered with a Sanwa JLX or Semitsu 70X. It can also come in Vewlix or Sega 2P layouts.
Nipe Arcade Originals is a premium source of custom controllers made of some of the finest woods known to man.
What sets the Clear - WASD+ apart from similar controllers is how it has extra keys on the right side of it.
The HING3DBOX is a 3D printed leverless controller that you can fold in half for easy carriage and storage.
The Oblong is a mini rectangle controller that comes in different colors, but more interestingly, there is an extra button.
Keybox Arcade strikes back with a timely release, the Keybox Impact, that has extra buttons for L3 and R3 functionality.
The Pocket is a mini all-key controller by Perfect Clear with two extra DSA keycaps on the upper right side.