Deathmark Prelate

In Commander, Deathmark Prelate rewards graveyard-heavy metas: by mid-game, most opponents have enough creature diversity in their bins that the lock covers a wide swath of mana values, disrupting combos and haymakers alike. It fits naturally in Orzhov or Grixis control shells that want passive disruption without spending mana each turn. In Legacy and Vintage, the graveyard fills fast enough that Deathmark Prelate can blank key spells on turn one or two, though those formats have enough graveyard hate and fast mana to race around it. Oathbreaker operates similarly to Commander at a smaller scale, where the reduced card pool makes the lock hit harder.