I consider having both gold Zelda NES carts a lucky find
I've actually heard that the grey Zelda carts are considered rare. I assume that's because they were a re-release. If that turns out to be the case, it may be one of the rarer NES game I own, although none are all that rare. Gargoyle's Quest II, Metal Storm, and Mighty Final Fight would probably be the ones that stand out.
the rarest game i have is probably conkers bad fur day for the n64 or ducktales 2 for the nes whats yours ?
Nice. Ducktales 2 is a game I would love to add to my collection.
SNES
I have some good rarer games on the SNES including boxed copies of Chrono Trigger and Earthbound, and cartridges of Demon's Crest and Robotrek. By far the rarest SNES game I have is E.V.O. Search for Eden. Had to drop $60 on that one in a pawn shop, but compared to what it goes for on eBay, it was a good deal.
N64
Nothing too special here. Rarest would probably be Goemon's Great Adventure.
GCN
I have the Legend of Zelda Collector's Edition disc for the Gamecube.