If you don't need 16 or more buttons: the VSLAB VSNOVA N14 is a fine option with chamfered acrylic, customizable art, and cool LED.
The Split is divided into two halves connected through a coiled detachable cable—and should be compatible with future modules by Ultra Arcade.
The TIKITAKA M3 doesn't have 16 buttons. It has 17, and the 17th button is a rare fully sized start button on the top panel's upper left.
The FRS Mini is a mini version of the bestselling FRS by Furin Arcade, and its 16 buttons mean that you have access to a dual layout.
The SticklessBox features a rare combination of Sanwa buttons and the GP2040-CE firmware—plus a convenient carrying handle.
RetroGameBoyz makes retro game controllers, including arcade sticks, which can also be used for modern fighting games.
The CounterHit Compact is the creation of a Seattle engineer, and its loop lets you attach the tiny CounterHit Nano controller.
Even though the MustFun Board looks like the Haute42 B16, it has some interesting differences, such as an onboard screen.