Confidence:StrongSolidPlausibleTentativeSpeculative

• Ioreth of the Healing House✓

  2U

  Legendary Creature — Human ClericU

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Kiki-Jiki, Mirror Breaker✓

  2RRR

  Legendary Creature — Goblin ShamanR

  Copy chain: one card creates hasty copies of a creature whose ability or ETB the partner exploits — the canonical Kiki-Jiki / Splinter Twin pattern.
• Loki's Scepter

  2R

  Legendary ArtifactR

  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.
• Nature's Chosen

  G

  Enchantment — AuraG

  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.
• Samut, Voice of Dissent

  3RG

  Legendary Creature — Human WarriorGRW

  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.
• Forensic Researcher

  2U

  Creature — Merfolk DetectiveU

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Kiora's Follower

  GU

  Creature — MerfolkGU

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

  2G

  Creature — Elf DruidG

  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.
• Norritt

  3B

  Creature — ImpB

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

  2U

  Enchantment — AuraU

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Seeker of Skybreak

  1G

  Creature — ElfG

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Saryth, the Viper's Fang

  2GG

  Legendary Creature — Human WarlockG

  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.
• Ith, High Arcanist

  5WU

  Legendary Creature — Human WizardUW

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

  G

  Creature — Elf ScoutG

  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.
• Maze of Ith

  LandC

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Vizier of Tumbling Sands

  2U

  Creature — Human ClericU

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

  2U

  Creature — Vedalken SoldierU

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• D'Vana Tendi, Optimistic Ensign

  1G/UG/U

  Legendary Creature — Orion ScientistGU

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

  2U

  Creature — ElementalU

  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.
• Niblis of the Breath

  2U

  Creature — SpiritU

  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.
• The Moment

  2

  Legendary ArtifactC

  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.
• North Pole Patrol

  2U

  Creature — Human Soldier AllyU

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Saheeli, the Sun's Brilliance

  UR

  Legendary Creature — Human ArtificerRU

  Paid copy loop: one card makes copies of a creature, and each copy readies the copier to copy again — but a copy or the untap costs mana every time. It runs for as long as you can pay: a mana sink, infinite only with infinite mana.
• The Jolly Balloon Man

  1RW

  Legendary Creature — Human ClownRW

  Paid copy loop: one card makes copies of a creature, and each copy readies the copier to copy again — but a copy or the untap costs mana every time. It runs for as long as you can pay: a mana sink, infinite only with infinite mana.
• Trickster Mage

  U

  Creature — Human SpellshaperU

  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.