One of the most impressive Pico project kits around is Peter ‘Bobricius' Misenko's RetroVGA, a Raspberry Pi Pico multi-retro computer which equips the microcontroller with a VGA output, DB9 joystick port, QWERTY keyboard, 3.5 mm audio output, integrated piezo speaker, USB port for input devices on supported emulators, and an SD card slot for storage.
The whole thing measures just 10 cm square, small enough to fit in a coat pocket, just in case you need to carry a retro microcomputer around with you. If you use a DB9 joystick, you'll need to reduce its cable length to around 30 cm, or it'll register false key presses.
The keyboard isn't quite full, lacking F-keys that are needed in some C64 titles, for example. The RetroVGA's sister device, the PICOZX (magpi.cc/picozx128)…