The FightBox K1 can come in white or black as well as K2 & K10 editions that have a joystick and more buttons respectively.
The KBGM-H04 is a dual layout controller with an aluminum alloy top and acrylic bottom. You can also add an extender for your wrists.
Just when you thought the T16 could not get any better, Haute42 gave us the T16-C with fast Crystal switches.
The Leme Tech One is a Smash controller that runs on the proprietary Leme Tech One firmware, which is HayBox-based and HayBox-compatible.
The DuelPad A16 is an acrylic controller that has 16 buttons with LED support and even comes with a modern console port.
The Ruyi Box is a stickless controller with 18 face buttons curved quite interestingly as well as two analog sticks.
The button layout of the Meisterbox M from Bavaria is supposed to make it the most ergonomic fighting game controller.
Cubs made a hybrid, the Cubstraption, that has a GameCube controller on the left and half of a box controller on the right.