If you come across a 17 button controller, odds are that 16 buttons are for directional and attack inputs, whereas the 17th button is a function button.
The 8BitDo Arcade Controller Pro adds a left pinky button and brings the right thumb button closer to the jump button.
The Mojhon Fight Master—which has buttons that vary in their levels of concavity, convexity, and flatness—has an optional wireless connection.
Akko transitions from keyboards into leverless controllers—with the Funbox's 17 buttons and adjustable Hall effect switches.
The Haute42 Emotion III-17 has four thumb buttons, a couple of which are pill-shaped, and it has a left pinky button (plus a lanyard loop).
The FightBox B-Pro is the head honcho of the B series, given that it's got 17 buttons—a good number to conquer tournaments.
Some of the SiTong H3's extra buttons are to be used by your left pinky, left thumb, right thumb, and right index finger.
The rumors are true: in addition to the buttons it's known for, SiTong has been selling controllers like the H2 controller with 17 buttons.
This is not the DuelPad Zen. It's the N17SP, and it has a split layout with 17 buttons—some of which are near the bottom.