In the past I've liked playing GameBoy Advance and other portable games on my Raspberry Pi (Retroarch) with official Raspberry Pi LCD display (7" 800 x 480) because the size of the display approximates the size of the original hardware displays and 480 is an integer scale for lots of consoles including the GameBoy Advance (160 vertical).
I've been trying to find similar small displays for using with my MiSTer and haven't found many good options. "Eyoyo" sells a few such displays with 480 vertical but reviews seem mixed on the quality of the display. "Elecrow" is another brand with some options. Another possibility would be monitors meant for monitoring video camera recordings (Atomos for ex) but those are very expensive/overkill and some of them display video signal info on the screen that can't always be turned off, depending on the brand/model. Maybe the Raspberry Pi 7" display could be adapted to work with the MiSTer but I don't know of any cases/adapters that do that currently (the display comes with just a ribbon cable connector and no case or power supply - it's meant to plug into a specific Raspberry Pi connector).
If anyone has used any small good quality monitors it would be great to know which ones are out there.
Thanks!