GameBoy Zero
I made this project around 2016. it’s basically a fully capable Raspberry Pi Zero made to play games on Retropie, it features 3 USB A ports (1 outside, 2 inside) and a direct connection to the Pi in case you want to run it to a screen to play with a controller instead of the built-in screen.
As an addon it has the SD card slot lined to the only cartridge reader of the original Game Boy, so if you like you can route a SD Card directly inside a Cartridge and use it to make it more aesthetic.
It also have a 3DS Stick in the middle of the case, so you can play different games that requires one.