Archghoul of Thraben

The tribal payoff that turns a Zombie's death into filtering rather than raw draw, and the distinction is the whole design. Most aggressive death-triggered engines hand you the top card outright and risk drowning you in lands; this one only fills your hand when what you find is another Zombie, and otherwise offers to bin whatever it uncovered. The choice built into that second clause is the smarter half: when the card you looked at is off-type (a land, a removal spell, anything that isn't a Zombie), you can send it to the graveyard instead of leaving it stranded, effectively digging toward your next Zombie the next time the ability fires. So a whiff still does work: it removes chaff from your library and sets up the following trigger, and it feeds the graveyard for whatever cares about cards being there. The result is a self-fueling filter that rewards a deck built dense with the creature type and punishes dilution with dead triggers rather than dead cards. It also triggers on its own death, so it never simply evaporates when it trades in combat: the last thing it does is dig for a replacement. Black has a deep bench of tribal card-advantage engines that ask you to commit to the creature type before they pay out; this one earns its keep by refusing to be a plain draw spell. It reads your library, sorts your Zombies from your chaff, and quietly cleans up before the next dig.