Confidence:StrongSolidPlausibleTentativeSpeculative

• Intruder Alarm✓

  2U

  EnchantmentU

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Grimgrin, Corpse-Born

  3UB

  Legendary Creature — Zombie WarriorBU

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Crackleburr

  1U/RU/R

  Creature — ElementalRU

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Elspeth, Storm Slayer

  3WW

  Legendary Planeswalker — ElspethW

  One card multiplies the tokens the other creates — a token doubler pointed at a steady token source.
• Sunstrike Legionnaire

  1W

  Creature — Human SoldierW

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• The Legend of Kuruk // Avatar Kuruk

  2UU

  Enchantment — Saga // Legendary Creature — AvatarU

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Westvale Abbey // Ormendahl, Profane Prince

  Land // Legendary Creature — DemonB

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Belisarius Cawl

  2WU

  Legendary Artifact Creature — HumanUW

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Transmogrant Altar

  3

  ArtifactB

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Skirsdag High Priest

  1B

  Creature — Human ClericB

  Token-fuel engine: one side keeps producing untapped tokens that pay the other's tap costs, and the output feeds the loop again — Squirrel Nest with Earthcraft is the classic shape.
• Reservoir Kraken

  2UU

  Creature — KrakenU

  Token-fuel engine: one side keeps producing untapped tokens that pay the other's tap costs, and the output feeds the loop again — Squirrel Nest with Earthcraft is the classic shape.
• Prosperous Partnership

  1RW

  EnchantmentRW

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Chained Brute

  1R

  Creature — DevilR

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Sky Hussar

  3WU

  Creature — Human KnightUW

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Selesnya Evangel

  GW

  Creature — Elf ShamanGW

  Token-fuel engine: one side keeps producing untapped tokens that pay the other's tap costs, and the output feeds the loop again — Squirrel Nest with Earthcraft is the classic shape.
• Aura of Dominion

  UU

  Enchantment — AuraU

  Token-fuel engine: one side keeps producing untapped tokens that pay the other's tap costs, and the output feeds the loop again — Squirrel Nest with Earthcraft is the classic shape.
• Midnight Guard

  2W

  Creature — Human SoldierW

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Tolarian Kraken

  4UU

  Creature — KrakenU

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Dragonbroods' Relic

  1G

  ArtifactBGRUW

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Black Carriage

  3BB

  Creature — HorseB

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Marjhan

  5UU

  Creature — SerpentU

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Lazotep Quarry

  Land — DesertC

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Altar Golem

  7

  Artifact Creature — GolemC

  Token-fuel engine: one side keeps producing untapped tokens that pay the other's tap costs, and the output feeds the loop again — Squirrel Nest with Earthcraft is the classic shape.
• Kithkeeper

  6W

  Creature — ElementalW

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Lita, Mechanical Engineer

  2W

  Legendary Artifact Creature — ArtificerW

  Lita, Mechanical Engineer untaps all (or many) permanents, refreshing Halo Fountain's tap activation.