If I did them all:
Counterfeit, HoP, IGG, Relic, Treasure Trove, Venture, Stash, Contraband, Royal Seal, Cache
Counterfeit is a lot better than the rest, though HoP is pretty sweet too. Playing a Relic every turn is actually a pretty nice attack. Treasure Trove is very nice in super strong engines and money but hard to include in a less consistent engine. I could see Treasure Trove moving above Relic and IGG, not sure. All the pure money producers are pretty bad cards, they are innocent additions to certain decks but rarely make a big impact. Venture's powers have been terribly exaggerated since forever. Contraband is a lot more interesting when looking at the board, it actually does something. I wanted to put Contraband over Venture, but even if you might consider Contraband you don't usually get one. Contraband might be worse than Royal Seal I guess.
edit: I forgot Stash (thanks eHalcyon).
edit2: I don't think "pure money producers" makes any sense as a label, but I think I meant: Venture, Royal Seal, Stash, (sort of Cache).