I know of the following
5-screw, gold, round Nintendo seal, no "hold reset when turning off the power" warning
3-screw, gold, round Nintendo seal
3-screw, gold, oval Nintendo seal
3-screw, gray, oval Nintendo seal
Mainly what I'm not sure of is if there are gold 5-screws WITH the "hold reset" warning, or if there are gold 3-screws WITHOUT the "hold reset" warning, or both, or neither, or any other sort of interesting variations (oval seal 5-screws or something nutty like that).
I'm not really trying to collect them or anything, I'm just curious. I've got the 5-screw, that's enough for me.
I'm also only really talking about US releases. I know there are probably Canadian ones and stuff that have differences (actually saw a Zelda 2 with a Mattel logo at a rental store way back in 88 or 89, blew my mind) but I'm not really looking for that sort of variation.