Tinker Welder

Artifact prison, filed on tcdecks under the older name MUD. It’s built on lands that produce more than one mana. Ancient Tomb taps for {C}{C} and deals you 2, City of Traitors taps for {C}{C} but gets sacrificed when you play another land, and Mind Stone and Thran Dynamo (a {4} artifact that taps for {C}{C}{C}) push the total higher. That mana curve is what lets a two-land opening deploy a lock piece the opponent can’t answer yet.

Sphere of Resistance makes every spell cost one more — a tax you barely feel with Tomb and Dynamo, and one that badly hurts a deck casting four one-mana spells a turn. Winter Orb stops players from untapping more than one land per untap step; again, your mana comes from artifacts and from lands that already produce double, so you keep functioning while they don’t.

Tangle Wire is the one that actually wins games. It enters with four fade counters, and at the beginning of each player’s upkeep that player taps an untapped artifact, creature or land for each counter. You tap out on your own turn deploying threats, so the symmetry is fake — they lose four permanents’ worth of a turn, then three, then two.

Tinker is the toolbox: {2}{U}, sacrifice an artifact as an additional cost, then search your library for an artifact and put it directly onto the battlefield. A tapped-out Mind Stone becomes Karn, Silver Golem or Triskelion. Karn is a 4/4 that can spend {1} to turn any noncreature artifact into a creature with power and toughness equal to its mana value — a spent Tangle Wire becomes a 3/3 attacker. Triskelion enters with three +1/+1 counters and removes them to deal 1 damage each, which handles Goblins and Elves on its own.

Goblin Welder is the engine that makes the whole thing recursive. Tap it to have a player simultaneously sacrifice an artifact they control and return an artifact card from their graveyard to the battlefield. Both targets have to belong to the same player, so aimed at yourself it resets a fading Tangle Wire or turns a spent Mind Stone into Karn for free — and aimed across the table it can trade the artifact they just played for whatever junk is already in their graveyard.

MUD folds to cheap artifact removal. Naturalize, Hull Breach and Shattering Pulse (which has buyback {3}) all take the deck apart, and a resolved Pernicious Deed is close to game over. Against blue the sideboard Defense Grid — every spell costs three more except on its controller’s turn — closes the counterspell window entirely.