Confidence:StrongSolidPlausibleTentativeSpeculative

• Reanimate

  B

  SorceryB

  Reanimate puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Grave Researcher // Reanimate

  2BB

  Creature — Troll Warlock // SorceryB

  Grave Researcher puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Priest of Fell Rites

  WB

  Creature — Human WarlockBW

  Priest of Fell Rites puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Animate Dead

  1B

  Enchantment — AuraB

  Animate Dead puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Exhume

  1B

  SorceryB

  Exhume puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Life // Death

  G1B

  Sorcery // SorceryBG

  Life puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Dance of the Dead

  1B

  Enchantment — AuraB

  Dance of the Dead puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Soul Exchange

  BB

  SorceryB

  Soul Exchange puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Rat King, Verminister

  1B

  Legendary Creature — Rat AvatarB

  Rat King, Verminister puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Song of Creation

  1GUR

  EnchantmentGRU

  Horde of Notions lets you cast/play from the graveyard, enabling Song of Creation's recursion loop.
• Baron Helmut Zemo

  BBB

  Legendary Creature — Human Noble VillainB

  Horde of Notions lets you cast/play from the graveyard, enabling Baron Helmut Zemo's recursion loop.
• Hydro-Man, Fluid Felon

  UU

  Legendary Creature — Elemental VillainU

  Horde of Notions lets you cast/play from the graveyard, enabling Hydro-Man, Fluid Felon's recursion loop.
• Shanid, Sleepers' Scourge

  1RWB

  Legendary Creature — Human KnightBRW

  Horde of Notions lets you cast/play from the graveyard, enabling Shanid, Sleepers' Scourge's recursion loop.
• Quintorius Kand

  3RW

  Legendary Planeswalker — QuintoriusRW

  Horde of Notions lets you cast/play from the graveyard, enabling Quintorius Kand's recursion loop.
• The Circle of Loyalty

  4WW

  Legendary ArtifactW

  Horde of Notions lets you cast/play from the graveyard, enabling The Circle of Loyalty's recursion loop.
• Jodah, the Unifier

  WUBRG

  Legendary Creature — Human WizardBGRUW

  Horde of Notions lets you cast/play from the graveyard, enabling Jodah, the Unifier's recursion loop.
• Kasla, the Broken Halo

  3URW

  Legendary Creature — Angel AllyRUW

  Horde of Notions lets you cast/play from the graveyard, enabling Kasla, the Broken Halo's recursion loop.
• Lavinia, Foil to Conspiracy

  1W/UW/U

  Legendary Creature — Human DetectiveUW

  Horde of Notions lets you cast/play from the graveyard, enabling Lavinia, Foil to Conspiracy's recursion loop.
• Runaway Steam-Kin

  1R

  Creature — ElementalR

  Horde of Notions lets you cast/play from the graveyard, enabling Runaway Steam-Kin's recursion loop.
• Fiery Gambit

  2R

  SorceryR

  Fiery Gambit untaps lands, fueling Horde of Notions's mana-hungry effect.
• Innocuous Researcher

  3G

  Creature — Centaur DetectiveG

  Innocuous Researcher untaps lands, fueling Horde of Notions's mana-hungry effect.
• Fire Lord Zuko

  RWB

  Legendary Creature — Human Noble AllyBRW

  Horde of Notions lets you cast/play from the graveyard, enabling Fire Lord Zuko's recursion loop.
• Yore-Tiller Nephilim

  WUBR

  Creature — NephilimBRUW

  Yore-Tiller Nephilim puts Horde of Notions onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Malcolm, the Eyes

  UR

  Legendary Creature — Siren PirateRU

  Horde of Notions lets you cast/play from the graveyard, enabling Malcolm, the Eyes's recursion loop.
• Deathbringer Liege

  2W/BW/BW/B

  Creature — HorrorBW

  Horde of Notions lets you cast/play from the graveyard, enabling Deathbringer Liege's recursion loop.