2000 Year Island

2000 Year Island is a non-canon island rumored to have a hidden treasure of "2000" (2千もの) gold pieces, though it's actually just Gaimon's fake (ニセモノ) gold tooth.

Geography
2000 Year Island is a small, hill-shaped island with a single palm tree in the middle.

Citizens
Gaimon is, non-canonically, the only resident of the island.

2000 Gold
Luffy and Nami travel to 2000 Year Island, hoping to find the 2000 Gold. They successfully find the rumored chest but, instead of gold pieces, discover that it's just Gaimon. He informs them that he got a fake gold tooth, angering Nami and causing Luffy to laugh.