Confidence:StrongSolidPlausibleTentativeSpeculative

• Argivian Archaeologist

  1WW

  Creature — Human ArtificerW

  Sacrifice-recursion with a catch: one card can return the other from the graveyard, but the return ability has an extra cost (sacrificing another creature, discarding a card, or tapping with no way to untap) the pair can't pay by itself. It works once — something else must keep supplying the fodder to make it repeatable.
• Trading Post

  4

  ArtifactC

  Sacrifice-recursion with a catch: one card can return the other from the graveyard, but the return ability has an extra cost (sacrificing another creature, discarding a card, or tapping with no way to untap) the pair can't pay by itself. It works once — something else must keep supplying the fodder to make it repeatable.
• Darling of the Masses

  2GW

  Creature — Elf CitizenGW

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

  3W

  Creature — Rhino DruidW

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

  G

  Legendary ArtifactG

  Mana loop: net-positive mana cycle between the two cards.
• Reckless Lackey

  R

  Creature — Goblin PirateR

  Mana loop: net-positive mana cycle between the two cards.
• Mr. House, President and CEO

  RWB

  Legendary Artifact Creature — HumanBRW

  Mana loop: net-positive mana cycle between the two cards.
• Currency Converter

  1

  ArtifactC

  Mana loop: net-positive mana cycle between the two cards.
• Stark Industries Executive

  R

  Creature — Human AdvisorR

  Mana loop: net-positive mana cycle between the two cards.
• Phelia, Exuberant Shepherd

  1W

  Legendary Creature — DogW

  Phelia, Exuberant Shepherd blinks (exiles and returns) a permanent, re-firing Courier's Briefcase's enter-the-battlefield effect.
• Forsworn Paladin

  B

  Creature — Human KnightB

  Mana loop: net-positive mana cycle between the two cards.
• Halo Fountain

  2W

  ArtifactW

  Both cards produce the same kind of effect (shared token subtype).
• Wizard's Rockets

  1

  ArtifactC

  Mana loop: net-positive mana cycle between the two cards.
• Phabine, Boss's Confidant

  3RGW

  Legendary Creature — Cat AdvisorGRW

  Both cards produce the same kind of effect (shared token subtype).
• Silk, Web Weaver

  2GW

  Legendary Creature — Spider Human HeroGW

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

  1W

  EnchantmentW

  Mana loop: net-positive mana cycle between the two cards.
• Goblin Welder

  R

  Creature — Goblin ArtificerR

  Goblin Welder returns creatures from the graveyard to the battlefield, re-firing Courier's Briefcase's enter-the-battlefield effect.
• Kitt Kanto, Mayhem Diva

  1RGW

  Legendary Creature — Cat Bard DruidGRW

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

  4WW

  Creature — Angel SoldierW

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

  1G

  Creature — SpiritG

  Mana loop: net-positive mana cycle between the two cards.
• Contested Game Ball

  2

  ArtifactC

  Mana loop: net-positive mana cycle between the two cards.
• Discerning Financier

  2W

  Creature — Human NobleW

  Mana loop: net-positive mana cycle between the two cards.
• Nahiri's Resolve

  3RW

  EnchantmentRW

  Nahiri's Resolve blinks (exiles and returns) a permanent, re-firing Courier's Briefcase's enter-the-battlefield effect.
• Thran Spider

  3

  Artifact Creature — SpiderC

  Mana loop: net-positive mana cycle between the two cards.
• Squall, SeeD Mercenary

  2WB

  Legendary Creature — Human Knight MercenaryBW

  Squall, SeeD Mercenary returns creatures from the graveyard to the battlefield, re-firing Courier's Briefcase's enter-the-battlefield effect.