Confidence:StrongSolidPlausibleTentativeSpeculative

• Mechanized Production

  2UU

  Enchantment — AuraU

  Alternate win condition: put the wincon on ONE of the tokens the other card produces (tokens of a batch share a name — Servos, Thopters, Treasures), and every further copy counts toward the same-name total.
• 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.
• Chevill, Bane of Monsters

  BG

  Legendary Creature — Human RogueBG

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Chevill, Bane of Monsters's death-trigger or removal payoff.
• Minsc & Boo, Timeless Heroes

  2RG

  Legendary Planeswalker — MinscGR

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Minsc & Boo, Timeless Heroes's death-trigger or removal payoff.
• Banon, the Returners' Leader

  RW

  Legendary Creature — Human Cleric RebelRW

  Graveyard pair: one card brings creatures back from the graveyard repeatedly (or a creature that returns itself), and the other keeps feeding the loop — a recurring reanimator with a payoff, or a sacrifice outlet with a self-recurring creature.
• Pia Nalaar, Consul of Revival

  RW

  Legendary Creature — Human ArtificerRW

  Both cards produce the same kind of effect (shared token subtype).
• The Meathook Massacre

  XBB

  Legendary EnchantmentB

  Breya, Etherium Shaper produces damage that can kill creatures, enabling The Meathook Massacre's death-trigger or removal payoff.
• Quest for the Gravelord

  B

  EnchantmentB

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Quest for the Gravelord's death-trigger or removal payoff.
• Gravecrawler

  B

  Creature — ZombieB

  Graveyard pair: one card brings creatures back from the graveyard repeatedly (or a creature that returns itself), and the other keeps feeding the loop — a recurring reanimator with a payoff, or a sacrifice outlet with a self-recurring creature.
• Bequeathal

  G

  Enchantment — AuraG

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Bequeathal's death-trigger or removal payoff.
• Kraven the Hunter

  1BG

  Legendary Creature — Human Warrior VillainBG

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Kraven the Hunter's death-trigger or removal payoff.
• Undead Sprinter

  BR

  Creature — ZombieBR

  Graveyard pair: one card brings creatures back from the graveyard repeatedly (or a creature that returns itself), and the other keeps feeding the loop — a recurring reanimator with a payoff, or a sacrifice outlet with a self-recurring creature.
• Toshiro Umezawa

  1BB

  Legendary Creature — Human SamuraiB

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Toshiro Umezawa's death-trigger or removal payoff.
• Malicious Affliction

  BB

  InstantB

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Malicious Affliction's death-trigger or removal payoff.
• Timeline Culler

  BB

  Creature — Drix WarlockB

  Graveyard pair: one card brings creatures back from the graveyard repeatedly (or a creature that returns itself), and the other keeps feeding the loop — a recurring reanimator with a payoff, or a sacrifice outlet with a self-recurring creature.
• Enduring Renewal

  2WW

  EnchantmentW

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Enduring Renewal's death-trigger or removal payoff.
• Glissa, the Traitor

  BGG

  Legendary Creature — Phyrexian Zombie ElfBG

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Glissa, the Traitor's death-trigger or removal payoff.
• Emeritus of Woe // Demonic Tutor

  3B1B

  Creature — Vampire Warlock // SorceryB

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Emeritus of Woe's death-trigger or removal payoff.
• Skullclamp

  1

  Artifact — EquipmentC

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Skullclamp's death-trigger or removal payoff.
• Lagomos, Hand of Hatred

  1BR

  Legendary Creature — Human ShamanBR

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Lagomos, Hand of Hatred's death-trigger or removal payoff.
• Ob Nixilis, Unshackled

  4BB

  Legendary Creature — DemonB

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Ob Nixilis, Unshackled's death-trigger or removal payoff.
• Assault Intercessor

  1WB

  Creature — Astartes WarriorBW

  Breya, Etherium Shaper produces damage that can kill creatures, enabling Assault Intercessor's death-trigger or removal payoff.
• Tenacious Underdog

  1B

  Creature — Human WarriorB

  Graveyard pair: one card brings creatures back from the graveyard repeatedly (or a creature that returns itself), and the other keeps feeding the loop — a recurring reanimator with a payoff, or a sacrifice outlet with a self-recurring creature.
• Skaab Ruinator

  1UU

  Creature — Zombie HorrorU

  Graveyard pair: one card brings creatures back from the graveyard repeatedly (or a creature that returns itself), and the other keeps feeding the loop — a recurring reanimator with a payoff, or a sacrifice outlet with a self-recurring creature.
• 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.).