The Granola Summit is an open source PLA Pro controller that has a port for additional console compatibility.
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.
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 Meisterboard from Bavaria is supposed to make it the most ergonomic fighting game controller.
The ST is a primarily stickless controller that is made of inox steel, has a see-through bottom panel, and glows in different colors.
It seems that DOIO took its creative liberties with the spacing of the KBGM-H03's buttons, especially the uppermost button.
The Mini•Dub is a smaller version of the 4TW by jonyfraze, and the primary difference is how the edges are mostly straight.