Confidence:StrongSolidPlausibleTentativeSpeculative

• Mikaeus, the Unhallowed✓

  3BBB

  Legendary Creature — Zombie ClericB

  Death replacement: a death-replacement grant on one card lets the other repeatedly die-and-return for combo (Mikaeus + Walking Ballista class).
• Baron Helmut Zemo

  BBB

  Legendary Creature — Human Noble VillainB

  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.
• Tinybones Joins Up

  B

  Legendary EnchantmentB

  Both cards trigger when a creature enters the battlefield — they fire together.
• Chandra, Flameshaper

  5RR

  Legendary Planeswalker — ChandraR

  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.
• Spreading Plague

  4B

  EnchantmentB

  Both cards trigger when a creature enters the battlefield — they fire together.
• Season of Growth

  1G

  EnchantmentG

  Both cards trigger when a creature enters the battlefield — they fire together.
• Kiora, Behemoth Beckoner

  2G/U

  Legendary Planeswalker — KioraGU

  Both cards trigger when a creature enters the battlefield — they fire together.
• Kiora, Master of the Depths

  2GU

  Legendary Planeswalker — KioraGU

  Both cards trigger when a creature enters the battlefield — they fire together.
• Faramir, Steward of Gondor

  1WU

  Legendary Creature — Human NobleUW

  Both cards trigger when a creature enters the battlefield — they fire together.
• Eye of Singularity

  3W

  World EnchantmentW

  Both cards trigger when a creature enters the battlefield — they fire together.
• Warden of the Grove

  2G

  Creature — HydraG

  Both cards trigger when a creature enters the battlefield — they fire together.
• Grist, Voracious Larva // Grist, the Plague Swarm

  G

  Legendary Creature — Insect // Legendary Planeswalker — GristBG

  Both cards trigger when a creature enters the battlefield — they fire together.
• Fecund Greenshell

  3GG

  Creature — Elemental TurtleG

  Both cards trigger when a creature enters the battlefield — they fire together.
• Lonis, Cryptozoologist

  GU

  Legendary Creature — Snake Elf ScoutGU

  Both cards trigger when a creature enters the battlefield — they fire together.
• Thassa, Deep-Dwelling

  3U

  Legendary Enchantment Creature — GodU

  Blink pair: one card can blink creatures repeatedly, and the other's ETB rewards every re-entry. Free-running only when the blink is free or refunded (Deadeye + Drake class); otherwise a repeatable value engine.
• Gladewalker Ritualist

  2G

  Creature — ShapeshifterG

  Both cards trigger when a creature enters the battlefield — they fire together.
• Garruk's Uprising

  2G

  EnchantmentG

  Both cards trigger when a creature enters the battlefield — they fire together.
• April O'Neil, Live on the Scene

  1U

  Legendary Creature — Human DetectiveU

  Both cards trigger when a creature enters the battlefield — they fire together.
• Sunstrike Legionnaire

  1W

  Creature — Human SoldierW

  Both cards trigger when a creature enters the battlefield — they fire together.
• Brainstealer Dragon

  5BB

  Creature — Dragon HorrorB

  Both cards trigger when a creature enters the battlefield — they fire together.
• Prowl, Stoic Strategist // Prowl, Pursuit Vehicle

  3W

  Legendary Artifact Creature — Robot // Legendary Artifact — VehicleW

  Both cards trigger when a creature enters the battlefield — they fire together.
• Marneus Calgar

  2WUB

  Legendary Creature — Astartes WarriorBUW

  Both cards trigger when a creature enters the battlefield — they fire together.
• Heronblade Elite

  2G

  Creature — Human WarriorG

  Both cards trigger when a creature enters the battlefield — they fire together.
• Righteous Valkyrie

  2W

  Creature — Angel ClericW

  Both cards trigger when a creature enters the battlefield — they fire together.
• Tribute to the World Tree

  GGG

  EnchantmentG

  Both cards trigger when a creature enters the battlefield — they fire together.