Confidence:StrongSolidPlausibleTentativeSpeculative

• Intruder Alarm✓

  2U

  EnchantmentU

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Thornbite Staff✓

  2

  Kindred Artifact — Shaman EquipmentC

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Sky Hussar

  3WU

  Creature — Human KnightUW

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Aura of Dominion

  UU

  Enchantment — AuraU

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Copperhorn Scout

  G

  Creature — Elf ScoutG

  Copperhorn Scout untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• White Plume Adventurer

  2W

  Creature — Orc ClericW

  White Plume Adventurer untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Jace, Ingenious Mind-Mage

  4UU

  Legendary Planeswalker — JaceU

  Jace, Ingenious Mind-Mage untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Harried Spearguard

  R

  Creature — Human SoldierR

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

  2R

  EnchantmentR

  Aggravated Assault untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Redcap Gutter-Dweller

  2RR

  Creature — Goblin WarriorR

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

  1GU

  Legendary Creature — Time Lord DoctorGU

  The Thirteenth Doctor untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Veteran Beastrider

  1GW

  Creature — Human KnightGW

  Veteran Beastrider untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Genku, Future Shaper

  2WU

  Legendary Creature — Moonfolk WizardUW

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

  2W

  Creature — SpiritW

  Drumbellower untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Gideon, Martial Paragon

  4W

  Legendary Planeswalker — GideonW

  Gideon, Martial Paragon untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Dazzling Theater // Prop Room

  3W2W

  Enchantment — Room // Enchantment — RoomW

  Dazzling Theater untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Intellectual Offering

  4U

  InstantU

  Intellectual Offering untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Ogre Chitterlord

  4RR

  Creature — Ogre WarriorR

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

  3GU

  Creature — Human WizardGU

  Prophet of Kruphix untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Éomer, Marshal of Rohan

  2RR

  Legendary Creature — Human KnightR

  Éomer, Marshal of Rohan untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Ratcatcher Trainee // Pest Problem

  1R2R

  Creature — Human Peasant // Instant — AdventureR

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

  2WBG

  Creature — ElephantBGW

  Ivorytusk Fortress untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Unstoppable Plan

  2U

  EnchantmentU

  Unstoppable Plan untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.
• Rat King, Pale Piper

  3B

  Legendary Creature — Rat AvatarB

  Both cards produce the same kind of effect (shared token subtype).
• Plargg, Dean of Chaos // Augusta, Dean of Order

  1R2W

  Legendary Creature — Orc Shaman // Legendary Creature — Human ClericRW

  Plargg, Dean of Chaos untaps all (or many) permanents, refreshing Marrow-Gnawer's tap activation.