Confidence:StrongSolidPlausibleTentativeSpeculative

• Mikaeus, the Unhallowed✓

  3BBB

  Legendary Creature — Zombie ClericB

  Death replacement: a death-replacement grant on one card lets the other repeatedly die-and-return for combo (Mikaeus + Walking Ballista class).
• Omnath, Locus of Rage

  3RRGG

  Legendary Creature — ElementalGR

  Both cards trigger when a creature dies — they fire together.
• 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.
• Bright-Palm, Soul Awakener

  1RGW

  Legendary Creature — Fox ShamanGRW

  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.
• 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.
• Ruinous Waterbending

  1BB

  Sorcery — LessonB

  Both cards trigger when a creature dies — they fire together.
• 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.
• Heliod, Sun-Crowned✓

  2W

  Legendary Enchantment Creature — GodW

  Counter + damage loop: one card spends counters to deal damage while the other replaces them on a hit (Heliod + Walking Ballista class).
• 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.
• 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.
• The Destined White Mage✓

  2W

  Legendary Creature — Human ClericW

  Counter + damage loop: one card spends counters to deal damage while the other replaces them on a hit (Heliod + Walking Ballista class).
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• Dr. McCoy, Surly Surgeon

  2WW

  Legendary Creature — Human DoctorW

  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.
• Ajani, Nacatl Pariah // Ajani, Nacatl Avenger

  1W

  Legendary Creature — Cat Warrior // Legendary Planeswalker — AjaniRW

  Both cards trigger when a creature dies — they fire together.
• Bloodline Recollector // Ancestral Craving

  1BB

  Creature — Vampire Warlock // InstantB

  Deathbringer Thoctar can kill creatures (with damage or by shrinking them), enabling Bloodline Recollector's death-trigger or removal payoff.
• Sarkhan's Unsealing

  3R

  EnchantmentR

  Sarkhan's Unsealing can kill creatures (with damage or by shrinking them), enabling Deathbringer Thoctar's death-trigger or removal payoff.