8BitDo Arcade Stick

 
The 8BitDo Arcade Stick is a fight stick controller is a heavy solidly built USB controller that can be read by the USB-A port on the Quadstick.
 
Its joystick and buttons follow the same mapping to Quadstick "usb_*" inputs as the DS4.   There is only one joystick and it is not analog.  The value it produces is either 0% or 100%.
 
8BitDo Arcade Stick is an example configuration spreadsheet that can be used to base a custom configuration on.
 
More information can be found on the 8BitDo website.
 
They can be purchased through Amazon.