Confidence:StrongSolidPlausibleTentativeSpeculative

• Obsessive Pursuit

  1B

  EnchantmentB

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

  G

  Creature — Goblin ShamanBGR

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

  G

  Creature — Human DruidGUW

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

  B

  SorceryB

  Reanimate puts Eel-Hounds onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Bard, Heir of Girion

  2WU

  Legendary Creature — Human ArcherUW

  Both cards trigger when a permanent attacks — they fire together.
• Garruk, Curse Breaker

  3GG

  Legendary Planeswalker — GarrukG

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

  3W

  Creature — Bird ClericW

  Both cards trigger when a permanent attacks — they fire together.
• Winota, Joiner of Forces

  2RW

  Legendary Creature — Human WarriorRW

  Both cards trigger when a permanent attacks — they fire together.
• Gallia of the Endless Dance

  RG

  Legendary Creature — SatyrGR

  Both cards trigger when a permanent attacks — they fire together.
• Jon Irenicus, Shattered One

  2UB

  Legendary Creature — Elf WizardBU

  Both cards trigger when a permanent attacks — they fire together.
• Clavileño, First of the Blessed

  1WB

  Legendary Creature — Vampire ClericBW

  Both cards trigger when a permanent attacks — they fire together.
• Grave Researcher // Reanimate

  2BB

  Creature — Troll Warlock // SorceryB

  Grave Researcher puts Eel-Hounds onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Twenty-Toed Toad

  3U

  Creature — Frog WizardU

  Both cards trigger when a permanent attacks — they fire together.
• Isshin, Two Heavens as One

  RWB

  Legendary Creature — Human SamuraiBRW

  Isshin, Two Heavens as One makes Eel-Hounds's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Hooded Blightfang

  2B

  Creature — SnakeB

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

  3R

  EnchantmentR

  Both cards trigger when a permanent attacks — they fire together.
• Dyadrine, Synthesis Amalgam

  XGW

  Legendary Artifact Creature — ConstructGW

  Both cards trigger when a permanent attacks — they fire together.
• Banon, the Returners' Leader

  RW

  Legendary Creature — Human Cleric RebelRW

  Both cards trigger when a permanent attacks — they fire together.
• Director Nick Fury

  URW

  Legendary Creature — Human Spy HeroRUW

  Both cards trigger when a permanent attacks — they fire together.
• Aloy, Savior of Meridian

  3GU

  Legendary Creature — Human WarriorGU

  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.
• Windcrag Siege

  1RW

  EnchantmentRW

  Windcrag Siege makes Eel-Hounds's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Priest of Fell Rites

  WB

  Creature — Human WarlockBW

  Priest of Fell Rites puts Eel-Hounds onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Ghalta and Mavren

  3GGWW

  Legendary Creature — Dinosaur VampireGW

  Both cards trigger when a permanent attacks — they fire together.
• M'Baku, Jabari Chieftain

  1GG

  Legendary Creature — Human Noble WarriorG

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