Can someone tell me what is included in each of the variant boxes? I'm looking to possibly purchase some, and would like to know which ones are worth buying for what I want/need.
The Complete Hero Variant Collection comes with every hero variant character card printed, with all new art, but not the base versions of the heroes (e.g. Dark Watch Expatriette but not the regular Expatriette you would get in the Rook City/Infernal Relics box)
The Ultimate Collector's case is a giant box to store ALL of the cards in, I beleive it comes with the Completionist Guise promo card.
The 5th Anniversary Foil Villain Collection has every villain character card in glorious foil! Including the regular villains from the core set and every expansion, the Vengeance style villains from Vengeance and the Villains of the Multiverse expansions, every variant villain character card (e.g. Heroic Infinitor) and the Character cards from OblivAeon.
I have no idea what "SotM: Promo Cards" refers to, could you link to it please?
If you just care about price, the non-foils will probably be less expensive. I will note that if you go with the non-foil villains The Dreamer will have a typo and I believe one other villain had a typo as well… I forget which. The errors aren’t that big a deal but they do effect gameplay.
You can get Completionist Guise with the Collector’s Case, the hero variant collection, or with The Foil Hero Collection.