Containment Priest completely shuts down Dredge, Oops and Reanimator strategies (when you come across them) and, frankly, has caused more immediate concessions than almost any other sideboard card
You can first get a targeted card from an opponents graveyard then exile the Lantern from your graveyard to filter mana
Among the various deck types, a Water-type deck could be the perfect choice to dominate the opposition , featuring some of the strongest ex cards in the game
Interestingly, Raichu is a popular choice among rivals as well
Its ceiling is a free Cut a Deal every turn or three (!) Treasure tokens, and its floor still leaves you with a lot of chump blockers
Each of those creature types focused on a two-color pair, but it was a departure from how we normally divide things