I already tried this before but for some reason it didn't work.
This is deck full of cards that unlock a Secret achievement if you put them in a deck, except for Fool's Bane and To My Side! because they are from other classes. There are other cards which unlock a Secret achievement upon simply viewing their page, with no deck required (which is why I don't have a deck for them).
Deck originally from: https://www.hearthpwn.com/decks/1280801-easy-secret-achievments-deck - I did make my own, but for some reason it didn't save properly.
I now have a reason to make my first deck on the site. Woo!