Confidence:StrongSolidPlausibleTentativeSpeculative

• Obsessive Pursuit

  1B

  EnchantmentB

  Both cards trigger when a permanent attacks — they fire together.
• Arna Kennerüd, Skycaptain

  2WUB

  Legendary Creature — Human KnightBUW

  Both cards trigger when a permanent attacks — they fire together.
• Hermes, Overseer of Elpis

  3U

  Legendary Creature — Elder WizardU

  Both cards trigger when a permanent attacks — they fire together.
• Bonny Pall, Clearcutter

  3GUU

  Legendary Creature — Giant ScoutGU

  Both cards trigger when a permanent attacks — they fire together.
• Nihiloor

  2WUB

  Legendary Creature — HorrorBUW

  Both cards trigger when a permanent attacks — they fire together.
• Dreadhorde Invasion

  1B

  EnchantmentB

  Both cards trigger when a permanent attacks — they fire together.
• Invasion of Tarkir // Defiant Thundermaw

  1R

  Battle — Siege // Creature — DragonR

  Both cards trigger when a permanent attacks — they fire together.
• Soaring Thought-Thief

  UB

  Creature — Human RogueBU

  Both cards trigger when a permanent attacks — they fire together.
• Amazing Alliance

  1WW

  EnchantmentW

  Both cards trigger when a permanent attacks — they fire together.
• Powerstone Minefield

  2RW

  EnchantmentRW

  Both cards trigger when a permanent attacks — they fire together.
• Alibou, Ancient Witness

  3RW

  Legendary Artifact Creature — GolemRW

  Both cards trigger when a permanent attacks — they fire together.
• Selfless Samurai

  1W

  Creature — Fox SamuraiW

  Both cards trigger when a permanent attacks — they fire together.
• Misty Mountains Raider

  4R

  Creature — Goblin SoldierR

  Both cards trigger when a permanent attacks — they fire together.
• Path of Bravery

  2W

  EnchantmentW

  Both cards trigger when a permanent attacks — they fire together.
• Guide of Souls

  W

  Creature — Human ClericW

  Both cards trigger when a permanent attacks — they fire together.
• Craig Boone, Novac Guard

  1RW

  Legendary Creature — Human SoldierRW

  Both cards trigger when a permanent attacks — they fire together.
• The Tenth Doctor

  3UR

  Legendary Creature — Time Lord DoctorRU

  Both cards trigger when a permanent attacks — they fire together.
• Mishra, Claimed by Gix

  2BR

  Legendary Creature — Phyrexian Human ArtificerBR

  Both cards trigger when a permanent attacks — they fire together.
• Grolnok, the Omnivore

  2GU

  Legendary Creature — FrogGU

  Both cards trigger when a permanent attacks — they fire together.
• Varina, Lich Queen

  1WUB

  Legendary Creature — Zombie WizardBUW

  Both cards trigger when a permanent attacks — they fire together.
• Echoing Assault

  4R

  EnchantmentR

  Both cards trigger when a permanent attacks — they fire together.
• 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.
• Zurzoth, Chaos Rider

  2R

  Legendary Creature — DevilR

  Both cards trigger when a permanent attacks — they fire together.
• Riddle Gate Gargoyle

  WU

  Artifact Creature — GargoyleUW

  Both cards trigger when a permanent attacks — they fire together.
• Cavalcade of Calamity

  1R

  EnchantmentR

  Both cards trigger when a permanent attacks — they fire together.