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.
• Captain of the Mists

  2U

  Creature — Human WizardU

  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.
• Tinybones Joins Up

  B

  Legendary EnchantmentB

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Faramir, Steward of Gondor

  1WU

  Legendary Creature — Human NobleUW

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Copperhorn Scout

  G

  Creature — Elf ScoutG

  Copperhorn Scout untaps all (or many) permanents, refreshing Romana II's tap activation.
• Miles "Tails" Prower

  1WU

  Legendary Creature — Fox ArtificerUW

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Tezzeret, Cruel Captain

  3

  Legendary Planeswalker — TezzeretC

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Fecund Greenshell

  3GG

  Creature — Elemental TurtleG

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Lagrella, the Magpie

  GWU

  Legendary Creature — Human SoldierGUW

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Gladewalker Ritualist

  2G

  Creature — ShapeshifterG

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• White Plume Adventurer

  2W

  Creature — Orc ClericW

  White Plume Adventurer untaps all (or many) permanents, refreshing Romana II's tap activation.
• Garruk's Uprising

  2G

  EnchantmentG

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Sunstrike Legionnaire

  1W

  Creature — Human SoldierW

  Copy chain: one card creates hasty copies of a creature whose ability or ETB the partner exploits — the canonical Kiki-Jiki / Splinter Twin pattern.
• Prowl, Stoic Strategist // Prowl, Pursuit Vehicle

  3W

  Legendary Artifact Creature — Robot // Legendary Artifact — VehicleW

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Jace, Ingenious Mind-Mage

  4UU

  Legendary Planeswalker — JaceU

  Jace, Ingenious Mind-Mage untaps all (or many) permanents, refreshing Romana II's tap activation.
• Tribute to the World Tree

  GGG

  EnchantmentG

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Arcades, the Strategist

  1GWU

  Legendary Creature — Elder DragonGUW

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Sarinth Steelseeker

  1G

  Creature — Human Artificer ScoutG

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Aggravated Assault

  2R

  EnchantmentR

  Aggravated Assault untaps all (or many) permanents, refreshing Romana II's tap activation.
• Killian, Decisive Mentor

  1WB

  Legendary Creature — Human WarlockBW

  Copy chain: one card creates hasty copies of a creature whose ability or ETB the partner exploits — the canonical Kiki-Jiki / Splinter Twin pattern.
• Dinosaur Egg

  1G

  Creature — Dinosaur EggG

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Legolas Greenleaf

  2G

  Legendary Creature — Elf ArcherG

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• The Mighty Thor, Jane Foster

  1WU

  Legendary Creature — Human God HeroUW

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Tetzin, Gnome Champion // The Golden-Gear Colossus

  URW

  Legendary Artifact Creature — Gnome // Legendary Artifact Creature — GnomeRUW

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.
• Dire Undercurrents

  3U/BU/B

  EnchantmentBU

  Copy engine: one card makes a copy of a creature every turn, and the other's enter-the-battlefield effect rewards each copy. Real, repeatable value — the partner can't untap or re-enter the copier, so it never goes infinite.