Since you are searching for cards to kill anyway, and therefore need not worry about hard casting, right behind Shadow and Savagery would be Hunted Horror, in my opinion. 2 black for 7 counters is not something to ignore.Sideboard Riftsweepers and Naturalize though, because people tend to focus on messing up graveyard decks if they know that's how you play. Since official rulings on exile says it's faceup unless otherwise noted, Riftsweeper can pull back any card you would normally lose forever, and the Naturalize gets rid of things like Rest in Peace.
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