It's gotta be Sabby, because it's the only one that doesn't have a successor of sorts. I liked the mechanic, but the card was so meh. I never minded Coppersmith much, and Bank fill the same niche as "crapload of coins if you draw a big deck" card.
Adrian, I think that if Tribute was always nonterminal and gave other bonuses according to the cards revealed, people would like it more. You play several, and the odds sort of level out. As it is, revealing two nonactions will often stop your chain before it can start, making it very swingy. Ultimately, it needs support to become reliable enough, and then you usually don't need it anymore because it doesn't do anything that the support it requires can't do.