It's pretty nice to have a closet full of zelda stuff.... but do you have a Link lollipop? It's officially from nintendo, and all though it's gross to have kept the lollipop for so long... well whatever.
It's a stupid thing to add to a collection... but just something I suppose.
I'm not sure what kind of things you're looking for to add to the collection... but maybe some Zelda comicbooks?... if that counts as anything official