When I was a kid I had a gameboy camera and a gameboy printer.
It was basically a low-res instagram/polaroid hybrid.
Take a selfie (the camera rotated, pretty revolutionary at the time), add borders and effects in-software, print out a instant photo.
It was sort of like an instant portable photobooth, what with the borders and frames and decals and so on.
It felt pretty magical when I was young. As an older person it feels as if it's a niche that could probably still be filled profitably by someone with the right stuff and marketing.
The end mentions that it's supported by GBE+ ... though getting paper for the Game Boy Printer is a bit of a challenge for enthusiasts. Some have taken to cutting non-official thermal paper to the right size.
While, we're on the topic, GBE+ just had a birthday (both GBE and GBE+ were released on April 1).
A part that's not super clear here is that the gameboy link cable comms are basically SPI. Running this over an Arduino is probably the easiest way to use this today.
anyone know what connector the gameboy link cable uses? i actually have a gameboy printer and it would be fun to print to from a PC