What are all the Masterpieces?

There's

Super Mario Bros
Legend of Zelda
Ice Climbers
Kirby's Adventure
Star Fox 64
Earthbound
Super Metroid

Is that really all of them?

I think the original Donkey Kongs one of them.

I think I remember seein' OoT somewhere

Fire Emblem I think.

I recall Earthbound and FE being Japan only.

Earthbound isn't really linked to MOTHER 3 in America like it is in Japan, so it's possible it's still in but either changed to unlock under different conditions or just not shown on the US site to avoid assumptions. It'd be like... uhh, having a locked character from Final Fantasy Adventure and a character from Seiken Densetsu 3. Both in Japan are part of the Mana series, but the first was released under a different title, (I don't think) the fact they're in the same world is obvious at first sight, and in America you'd guess the FFA character was in if it was shown and have no clue it was related to SD3. Likewise, if you were playing and unlocked The Legend of Zelda: A Link to the Past, you wouldn't assume that pink haired Link was in the game, right?

Sorry, I couldn't think of a better comparison. It's also possible they actually just didn't include Earthbound because of that reason, rather then hiding it from the US view on the site cause certain characters weren't known at the point of the update.

I think there's also Zelda: Ocarina of Time (N64) and F-Zero (SNES).