I've started one. Please finish it.
- Games which put up a "YOU CAN'T PLAY THIS" screen when run in the wrong region
- Games which run in the wrong region but are broken and/or unplayable
- Games which run too fast/too slow
- Games which are part-optimised for PAL consoles (e.g. only the music is sped up)
- Games which are "fully" optimised for PAL consoles (and use 240 lines instead of 224)
Similar lists will need to happen for Saturn and Dreamcast games, but this is maybe the most pressing because region locking and optimisation is horrendously inconsistent on the Mega Drive.
Fix things, add things, whatever.