One can argue that Amazon is the most popular for ordering fightsticks, meaning controllers with a joystick, but it also has great leverless controllers.
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).
We can rave on and on about the benefits of the MS1, but its selling point is its unique right thumb button placement.
The Starburst is a mini leverless controller with 15 buttons, and you can tilt it to more than one angle for the comfort of your wrists.
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 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.
Even though the MustFun Board looks like the Haute42 B16, it has some interesting differences, such as an onboard screen.
At a first glance, you may think this is a DOIO controller, but in reality—this is the NLOFIN NLHX-ET01: a 16 button controller with LED.
The Haute42 V16 is a large yet light 16 button controller with textured matte keycaps and fast Shadow Hunting switches—plus shiny LED.