This is a theme I compiled that includes North American, European, and Japanese variations for Sega Mega Drive, Sega CD, Sega 32x, Super Nintendo, NES (only NA and JP), PC Engine, and PC Engine CD.
I am not the original artist, I just compiled them into a single usable theme
https://github.com/JoargTheBard/recalbox-multiregion-theme (Github for theme)
https://forum.recalbox.com/topic/3972/release-temporary-alternative-regional-recalbox-theme (link to original artist)