Confidence:StrongSolidPlausibleTentativeSpeculative

• Keiga, the Tide Star

  5U

  Legendary Creature — Dragon SpiritU

  Synergy between the two cards.
• Teferi, Temporal Pilgrim

  3UU

  Legendary Planeswalker — TeferiU

  Draw pair: both cards engage with card draw. With a damage-or-draw trigger between them they form a draw engine.
• The Locust God

  4UR

  Legendary Creature — GodRU

  Draw pair: both cards engage with card draw. With a damage-or-draw trigger between them they form a draw engine.
• Mindless Conscription

  2B

  EnchantmentB

  Draw pair: both cards engage with card draw. With a damage-or-draw trigger between them they form a draw engine.
• Rodolf Duskbringer

  5B

  Legendary Creature — Vampire AngelBW

  Damage + lifelink: lifelink converts damage on one side into life triggers the partner pays off — the canonical Heliod / Karlov family.
• Fiendish Panda

  2WB

  Creature — Bear DemonBW

  Damage + lifelink: lifelink converts damage on one side into life triggers the partner pays off — the canonical Heliod / Karlov family.
• Chasm Skulker

  2U

  Creature — Squid HorrorU

  Draw pair: both cards engage with card draw. With a damage-or-draw trigger between them they form a draw engine.
• Ominous Seas

  1U

  EnchantmentU

  Draw pair: both cards engage with card draw. With a damage-or-draw trigger between them they form a draw engine.
• Sothera, the Supervoid

  2BB

  Legendary EnchantmentB

  Both cards trigger when a creature dies — they fire together.
• Faramir, Prince of Ithilien

  2WU

  Legendary Creature — Human NobleUW

  Both cards produce the same kind of effect (shared token subtype).
• 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.
• Captivating Glance

  2U

  Enchantment — AuraU

  Captivating Glance temporarily takes control of an opponent's creature, and Jerren, Corrupted Bishop sacrifices it — the opponent loses the permanent for good.
• Hateful Eidolon

  B

  Enchantment Creature — SpiritB

  Both cards trigger when a creature dies — they fire together.
• The Meathook Massacre

  XBB

  Legendary EnchantmentB

  Both cards trigger when a creature dies — they fire together.
• Merieke Ri Berit

  WUB

  Legendary Creature — HumanBUW

  Merieke Ri Berit temporarily takes control of an opponent's creature, and Jerren, Corrupted Bishop sacrifices it — the opponent loses the permanent for good.
• The Serpent Society

  1BG

  Legendary Creature — Human Snake VillainBG

  Both cards trigger when a creature dies — they fire together.
• Endless Evil

  2U

  Enchantment — AuraU

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

  1WU

  Legendary Creature — Human NobleUW

  Both cards produce the same kind of effect (shared token subtype).
• Wight

  1B

  Creature — Zombie SoldierB

  Both cards trigger when a creature dies — they fire together.
• Meren of Clan Nel Toth

  2BG

  Legendary Creature — Human ShamanBG

  Both cards trigger when a creature dies — they fire together.
• Edea, Possessed Sorceress

  2UBR

  Legendary Creature — Human WarlockBRU

  Both cards trigger when a creature dies — they fire together.
• 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

  Both cards trigger when a creature dies — they fire together.
• Varchild, Betrayer of Kjeldor

  2R

  Legendary Creature — Human KnightR

  Varchild, Betrayer of Kjeldor temporarily takes control of an opponent's creature, and Jerren, Corrupted Bishop sacrifices it — the opponent loses the permanent for good.
• 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.