Reveka, Wizard Savant

A repeatable damage source that costs you nothing but tempo, and the tempo cost is the whole design. Tapping to deal two is a strong rate for a permanent that can fire turn after turn, so the balance lever is the skip clause: Reveka stays tapped through the following untap step, meaning every shot buys a full turn of vulnerability. That cadence (fire, sit defenseless, untap, fire again) kept the effect honest in an era when Wizards was still feeling out how cheap recurring direct damage could be on a permanent. The 0/1 frame is part of the calculus too: a body that contributes nothing in combat and survives almost nothing as a blocker, so the card is pure utility, a slow drip of two-point removal that can also be aimed at a player's life total as incremental burn. The friction is what makes it interesting; a Reveka that untapped normally would have been a very different, and probably overcorrected, card. It is one of the cleaner designs in its set, a tidy expression of the principle that a recurring ability does not need a per-use mana cost if it taxes you in time instead.