PLA is definitely one of the most popular plastics to make fighting game controllers out of, and being biodegradable is nice.
The FS-MINI by Tbox is a mini controller that is available in lever and leverless editions. It can also come in preassembled or DIY formats.
Remember the banned GafroBox? Well, Gafro released LI.TERAS, which brings back the same goodness—plus interchangeable modules.
Available in preassembled & DIY formats, the PadBox is a plastic D-pad controller with Sanwa buttons, Omron switches, and custom LED.
The Granola Summit is an open source PLA Pro controller that has a port for additional console compatibility.
The Atari Fire Controller is only one of many retro arcade sticks that SuperBox64 makes with a joystick, trackball, spinner, and buttons.
If there's a most innovative award, the JTechWorkshop would definitely be a contender. Its leverless controllers have highly custom layouts.
When not making wooden accessories for tech, StepUpSFF makes stuff like the Retro Lever-less Arcade Controller (also in WASD format).
The KeebBrawler-01 is a mini stickless controller that most notably has a wide jump button and unique attack button layout.