Confidence:StrongSolidPlausibleTentativeSpeculative

• Court of Garenbrig

  1GG

  EnchantmentG

  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.
• Hollowmurk Siege

  BG

  EnchantmentBG

  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.
• Iron Spider, Stark Upgrade

  3

  Legendary Artifact Creature — Spider HeroC

  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.
• Freed from the Real✓

  2U

  Enchantment — AuraU

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

  3G

  Legendary Creature — Human PilotG

  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.
• Benevolent Hydra

  XGG

  Creature — HydraG

  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.
• Bristly Bill, Spine Sower✓

  1G

  Legendary Creature — Plant DruidG

  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.
• Pemmin's Aura✓

  1UU

  Enchantment — AuraU

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Zimone, Paradox Sculptor

  2GU

  Legendary Creature — Human WizardGU

  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.
• Ornery Tumblewagg

  2G

  Creature — Brushwagg MountG

  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.
• Hydra's Growth

  2G

  Enchantment — AuraG

  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.
• Byrke, Long Ear of the Law

  4GW

  Legendary Creature — Rabbit SoldierGW

  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.
• 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.
• Turtle Van

  3

  Artifact — VehicleC

  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.
• Level Up

  1G

  Enchantment — AuraG

  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.
• The First Tyrannic War

  2GUR

  Enchantment — SagaGRU

  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.
• Sword of Hours

  2

  Artifact — EquipmentC

  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.
• Seismic Tutelage

  3G

  Enchantment — AuraG

  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.
• Arcade Cabinet

  3

  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.
• Lita, Mechanical Engineer

  2W

  Legendary Artifact Creature — ArtificerW

  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 Crystalline Crawler's tap activation.
• 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.
• White Plume Adventurer

  2W

  Creature — Orc ClericW

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

  4UU

  Legendary Planeswalker — JaceU

  Jace, Ingenious Mind-Mage untaps all (or many) permanents, refreshing Crystalline Crawler's tap activation.
• Aggravated Assault✓

  2R

  EnchantmentR

  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.