Confidence:StrongSolidPlausibleTentativeSpeculative

• Intellectual Offering

  4U

  InstantU

  Intellectual Offering untaps all (or many) permanents, refreshing Mourner's Shield's tap activation.
• Unstoppable Plan

  2U

  EnchantmentU

  Unstoppable Plan untaps all (or many) permanents, refreshing Mourner's Shield's tap activation.
• Unwinding Clock

  4

  ArtifactC

  Unwinding Clock untaps all (or many) permanents, refreshing Mourner's Shield's tap activation.
• Seedborn Muse

  3GG

  Creature — SpiritG

  Seedborn Muse untaps all (or many) permanents, refreshing Mourner's Shield's tap activation.
• Paradox Engine

  5

  Legendary ArtifactC

  Paradox Engine untaps all (or many) permanents, refreshing Mourner's Shield's tap activation.
• Dramatic Reversal

  1U

  InstantU

  Dramatic Reversal untaps all (or many) permanents, refreshing Mourner's Shield's tap activation.
• Blinkmoth Infusion

  12UU

  InstantU

  Blinkmoth Infusion untaps all (or many) permanents, refreshing Mourner's Shield's tap activation.
• The Eternal Wanderer

  4WW

  Legendary PlaneswalkerW

  The Eternal Wanderer blinks (exiles and returns) a permanent, re-firing Mourner's Shield's enter-the-battlefield effect.
• Jolted Awake

  W

  SorceryW

  Jolted Awake returns creatures from the graveyard to the battlefield, re-firing Mourner's Shield's enter-the-battlefield effect.
• Phelia, Exuberant Shepherd

  1W

  Legendary Creature — DogW

  Phelia, Exuberant Shepherd blinks (exiles and returns) a permanent, re-firing Mourner's Shield's enter-the-battlefield effect.
• Explosive Getaway

  3RW

  SorceryRW

  Explosive Getaway blinks (exiles and returns) a permanent, re-firing Mourner's Shield's enter-the-battlefield effect.
• Chandra, Flamecaller

  4RR

  Legendary Planeswalker — ChandraR

  Chandra, Flamecaller deals damage to many targets, fueling Mourner's Shield's damage-payoff trigger.
• The Mighty Thor, Jane Foster

  1WU

  Legendary Creature — Human God HeroUW

  The Mighty Thor, Jane Foster blinks (exiles and returns) a permanent, re-firing Mourner's Shield's enter-the-battlefield effect.
• Aerial Extortionist

  3WW

  Creature — Bird SoldierW

  Aerial Extortionist exiles a permanent and lets its owner cast it again — the recast fires Mourner's Shield's cast trigger or its enter-the-battlefield effect.
• What Must Be Done

  3WW

  SorceryW

  What Must Be Done returns creatures from the graveyard to the battlefield, re-firing Mourner's Shield's enter-the-battlefield effect.
• The Mind Stone

  1W

  Legendary Artifact — Infinity StoneW

  The Mind Stone blinks (exiles and returns) a permanent, re-firing Mourner's Shield's enter-the-battlefield effect.
• Let the Galaxy Burn

  X5R

  SorceryR

  Let the Galaxy Burn deals damage to many targets, fueling Mourner's Shield's damage-payoff trigger.
• Chain Reaction

  2RR

  SorceryR

  Chain Reaction deals damage to many targets, fueling Mourner's Shield's damage-payoff trigger.
• Jack of Hearts, Volatile Hero

  1RR

  Legendary Creature — Alien Human HeroR

  Jack of Hearts, Volatile Hero deals damage to many targets, fueling Mourner's Shield's damage-payoff trigger.
• Elrond, Moon-Reader

  2U

  Legendary Creature — Elf NobleU

  Elrond, Moon-Reader blinks (exiles and returns) a permanent, re-firing Mourner's Shield's enter-the-battlefield effect.
• Godo, Bandit Warlord

  5R

  Legendary Creature — Human BarbarianR

  Godo, Bandit Warlord grants an extra combat phase, enabling Mourner's Shield's combat-trigger payoff.
• Don & Leo, Problem Solvers

  3W/UW/U

  Legendary Creature — Mutant Ninja TurtleUW

  Don & Leo, Problem Solvers blinks (exiles and returns) a permanent, re-firing Mourner's Shield's enter-the-battlefield effect.
• Temporal Tribulation

  2U

  InstantU

  Temporal Tribulation blinks (exiles and returns) a permanent, re-firing Mourner's Shield's enter-the-battlefield effect.
• All-Out Assault

  2RWB

  EnchantmentBRW

  All-Out Assault grants an extra combat phase, enabling Mourner's Shield's combat-trigger payoff.
• Goblin Welder

  R

  Creature — Goblin ArtificerR

  Goblin Welder returns creatures from the graveyard to the battlefield, re-firing Mourner's Shield's enter-the-battlefield effect.