My Game Boy Printer still has plenty of life left in it.
Power duo
Essentially a receipt printer for kids, the Game Boy Printer uses thermal paper (and 6 AA batteries) to print stamp-sized images from a surprisingly robust list of games. Of course, I had to run a few tests using my favorite subject with the classic Game Boy Camera/Printer combo, such as this multiprint test with 0 margin.
Triple Mochi
Just for fun, here are some images from Super Mario Bros. Deluxe (top/middle) and Austin Powers: Oh, Behave! (bottom), the latter of which has a modes where you can just print whatever you type on screen, and even a "realtime" calculator feature that prints as you enter calculations. Developed by Rockstar, the game is presented like a mobile "OS" and is bizarre in its own right, but maybe I'll write about it another time (plus its companion game, Welcome to My Underground Lair, because every Game Boy title needed two versions in a post-Pokemon world).
Super Austin Powers Bros Deluxe
Finally, a handful of games have illustrations that you can print, such as Link's Awakening DX and Pocket Puyo Puyo~n.
Pocket Puyo Puyo~n, currently the best way to get a tiny, low-res printout of Arle
Some of the fun is lost without the sticker backing of the original printer paper but hey tape exists.