Confidence:StrongSolidPlausibleTentativeSpeculative

• Harold and Bob, First Numens

  2G

  Legendary Creature — Treefolk MutantG

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

  1G

  Enchantment — ClassG

  Counter synergy: both cards work with the same kind of counters, so their effects stack in a counters deck. Not necessarily a closed loop on its own.
• Animation Module

  1

  ArtifactC

  Counter synergy: both cards work with the same kind of counters, so their effects stack in a counters deck. Not necessarily a closed loop on its own.
• Forge of Heroes

  LandC

  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 Monumental Facade

  Land — SphereC

  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.
• Kaito, Dancing Shadow

  2UB

  Legendary Planeswalker — KaitoBU

  Both cards trigger on damage dealt — they fire together.
• Archivist of Gondor

  2U

  Creature — Human AdvisorU

  Both cards trigger on damage dealt — they fire together.
• Frostcliff Siege

  1UR

  EnchantmentRU

  Both cards trigger on damage dealt — they fire together.
• Sphere Grid

  1G

  EnchantmentG

  Both cards trigger on damage dealt — they fire together.
• Stick, Fearless Mentor

  1R

  Legendary Creature — Human Monk HeroR

  Both cards trigger on damage dealt — they fire together.
• Knuckles the Echidna

  2RR

  Legendary Creature — Echidna WarriorR

  Both cards trigger on damage dealt — they fire together.
• Toralf, God of Fury // Toralf's Hammer

  2RR1R

  Legendary Creature — God // Legendary Artifact — EquipmentR

  Both cards trigger on damage dealt — they fire together.
• Daredevil, Fearless Fighter

  2R

  Legendary Creature — Human HeroR

  Both cards trigger on damage dealt — they fire together.
• Goro-Goro and Satoru

  UBR

  Legendary Creature — Goblin HumanBRU

  Both cards trigger on damage dealt — they fire together.
• Araña, Heart of the Spider

  1RW

  Legendary Creature — Spider Human HeroRW

  Both cards trigger on damage dealt — they fire together.
• Kutzil, Malamet Exemplar

  1GW

  Legendary Creature — Cat WarriorGW

  Both cards trigger on damage dealt — they fire together.
• Kaust, Eyes of the Glade

  R/WG

  Legendary Creature — Dryad DetectiveGRW

  Both cards trigger on damage dealt — they fire together.
• Grenzo, Havoc Raiser

  RR

  Legendary Creature — Goblin RogueR

  Both cards trigger on damage dealt — they fire together.
• Kassandra, Eagle Bearer

  1RW

  Legendary Creature — Human Assassin WarriorRW

  Both cards trigger on damage dealt — they fire together.
• Oona's Blackguard

  1B

  Creature — Faerie RogueB

  Both cards trigger on damage dealt — they fire together.
• Sygg, Wanderwine Wisdom // Sygg, Wanderbrine Shield

  1U

  Legendary Creature — Merfolk Wizard // Legendary Creature — Merfolk RogueUW

  Both cards trigger on damage dealt — they fire together.
• Hooded Blightfang

  2B

  Creature — SnakeB

  Both cards trigger on damage dealt — they fire together.
• Kodama of the West Tree

  2G

  Legendary Creature — SpiritG

  Both cards trigger on damage dealt — they fire together.
• Glitch Interpreter

  2U

  Creature — Human WizardU

  Both cards trigger on damage dealt — they fire together.
• The Beast, Deathless Prince

  2BR

  Legendary Creature — DemonBR

  Both cards trigger on damage dealt — they fire together.