Wow, nice on the SuperGrafx and the SMS stuff!
I have a couple carts with a sticker that says like Sega for the 90's but that is the only weird SMS stuff I've got. I've been slowly trying to pick up US games for the system but prices are really going up now for some reason!
Variant collecting is completely retarded - *technically* the "Sega for the 90's"-stickered games are also variants, but they're so impossibly hard to identify via auction, and there are no other differences except for the stupid sticker, and maybe a copyright or trademark on the back of the manual.
Most people don't consider them part of a "complete" set, but you can drive yourself mad trying to collect every single version and variation of things like this. If you think that's bad, there are an insane amount of variants for the Genesis and SNES (stuff like Castlevania Bloodlines Konami Clamshell vs. Majesco Cardboard version 1 vs. Majesco Cardboard version 2...et al).
I decided to draw the line at the full NTSC set and "official" variants, and call it a day, haha.