Aether Rift

Random discard as a reanimation engine, paid for once and then running on autopilot: every upkeep, a card leaves your hand blind, and when it happens to be a creature, that creature returns to the battlefield unless any player pays five life to stop it. The price the card charges is total loss of choice. You cannot aim the discard, so the build has to make every card you might shed either acceptable (lands, situational answers) or actively good (a fattie you would rather have in play than stranded in your hand). That constraint is the whole deckbuilding puzzle: the more your hand collapses toward huge, hard-to-cast threats, the more often the random discard becomes a free comes-into-play swing whose mana value dwarfs the three you spent here. The reanimation runs only in your favor; the creature comes back to your side, and the only lever anyone gets is a punisher clause, the option to pay five life to keep it in the graveyard. That turns each upkeep into a tax the table either absorbs or refuses, depending on how much the returning creature would hurt them, and a deck stacked with must-answer threats can drain opponents over a few turns just from the life they pay to stop it. Where the targeted reanimation spells of its era did the job once on demand, this is a recurring lottery you have weighted toward yourself, randomness and all, which is exactly what keeps it a build-around rather than a clean combo line.