Who has all the expansions?
We the short answer is ... I do, but not REALLY, because if you include the 2nd Editions, Big Boxes, Special Editions and Non-English versions, I suspect only Donald X might be the only one. And I doubt anyone has that kind of money.
I have all the regular sets and 2nd editions in English. I have just one of the Japanese rethemes, and a couple random other languages of the original main set. I don't have the other other-language-only products, like Big Boxes with different stuff or the Dutch intro product thing. I have the promos in English in both versions, and Stash in Japanese, which came with one volume of their strategy guide; I have just that volume, which they randomly sent me. I don't have the doll with nipples. I have the promotional tin of mints, the little wooden box, and the tote bag.
It's hard to have a complete collection of anything worth collecting, without defining your collection in such a way as to omit some stuff. I once had a complete collection of Steve Gerber Howard the Ducks in comic-book form (including e.g. the Man-Things); I didn't care about the non-Gerber stuff, and sure didn't have e.g. the newspaper strips, which he did write (though I have the Marvel Special Edition, which is oversize). But years later they brought Gerber back somehow and man I don't have those.