Confidence:StrongSolidPlausibleTentativeSpeculative

• 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.
• 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, 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.
• 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.
• Lagrella, the Magpie

  GWU

  Legendary Creature — Human SoldierGUW

  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.
• Sunstrike Legionnaire

  1W

  Creature — Human SoldierW

  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.
• 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.
• Tribute to the World Tree

  GGG

  EnchantmentG

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

  1GWU

  Legendary Creature — Elder DragonGUW

  Both cards trigger when a creature enters the battlefield — they fire together.
• Bess, Soul Nourisher

  1GW

  Legendary Creature — Human CitizenGW

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

  GG

  EnchantmentG

  Both cards trigger when a creature enters the battlefield — they fire together.
• Slash, Reptile Rampager

  3RR

  Legendary Creature — Mutant Berserker TurtleR

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

  1G

  Creature — Dinosaur EggG

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

  2G

  Legendary Creature — Elf ArcherG

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

  1W

  Creature — Phyrexian Human ClericW

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

  3B

  EnchantmentB

  Both cards trigger when a creature enters the battlefield — they fire together.
• Elas il-Kor, Sadistic Pilgrim

  WB

  Legendary Creature — Phyrexian Kor ClericBW

  Both cards trigger when a creature enters the battlefield — they fire together.
• Mirrorhall Mimic // Ghastly Mimicry

  3U

  Creature — Spirit // Enchantment — AuraU

  One-shot copy enabler: a card enters as a copy of another (Phantasmal Image, Body Double, Phyrexian Metamorph), firing the partner's substantive ETB once. Not a repeating chain — fires once on entry — but valuable when the partner's ETB is combo-grade (graveyard reanimator, mana doubler, etc.).