There are not many 18 button controllers on the market, and the Mad Catz NEKO solves this problem—plus many other things...
Junkfood Custom Arcades came up with the SWORL to solve the Snack Box Micro's limitation of only being for fighting games.
Mortal Kombat players can buy the FightBox R8 with old school Happ parts—or the R8-J edition with Sanwa parts (and a more modern enclosure).
Wooden Pan makes wooden controllers in Austria, so if you're nearby or like its controllers enough, you can request long distance shipping!
The Huevos Puncheros is a case that is made of leftover acrylic and some filament. Its wrist rest is magnetically detachable!
You can buy Akekon Dojo's DP-5 regular or mini version with 11 or 13 buttons and at least three color options.
Haute42 continues its journey of making fighting game controllers for every need, such as the E16 Mirrored, which is for left handed players.
The GRAPHT iO is endorsed by Tachikawa, used by Kobayan, and comes in lever or leverless format—as well as DIY or preassembled format.