Confidence:StrongSolidPlausibleTentativeSpeculative

• Phial of Galadriel

  3

  Legendary ArtifactC

  Lifegain pair: one card gains life while the other rewards lifegain. They reinforce each other in a lifegain deck.
• Shifting Woodland

  LandG

  Graveyard copier: one card stocks the graveyard (mill, surveil, dredge) and the other can repeatedly become a copy of a card that's there, borrowing its abilities without recasting it — the Shifting Woodland + Aftermath Analyst shape.
• Elrond, Moon-Reader

  2U

  Legendary Creature — Elf NobleU

  A-Uurg, Spawn of Turg has activated abilities that aren't mana abilities, fueling Elrond, Moon-Reader's activation-trigger.