WASD-style joystick for vintage computers. With an added Arduino Pro Micro you can use it as a USB-keyboard, so if you wanted a DIY streamdeck or Macro-keyboard - then the C64 JoyKEY can do that as well.
Knock-off of the Elektor Formant Synthesizer project with the initial goal of being quasi-authentic and secondary goal undecided. Probably tweaks of some kind.