Confidence:StrongSolidPlausibleTentativeSpeculative

• Intruder Alarm✓

  2U

  EnchantmentU

  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.
• Reanimate

  B

  SorceryB

  Reanimate puts Ulamog's Dreadsire 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 Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Sky Hussar

  3WU

  Creature — Human KnightUW

  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.
• Aura of Dominion

  UU

  Enchantment — AuraU

  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 Ulamog's Dreadsire's tap activation.
• Yore-Tiller Nephilim

  WUBR

  Creature — NephilimBRUW

  Yore-Tiller Nephilim puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• White Plume Adventurer

  2W

  Creature — Orc ClericW

  White Plume Adventurer untaps all (or many) permanents, refreshing Ulamog's Dreadsire's tap activation.
• Sefris of the Hidden Ways

  WUB

  Legendary Creature — Human WizardBUW

  Sefris of the Hidden Ways puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Recurring Nightmare

  2B

  EnchantmentB

  Recurring Nightmare puts Ulamog's Dreadsire 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 Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Veteran Beastrider

  1GW

  Creature — Human KnightGW

  Veteran Beastrider untaps all (or many) permanents, refreshing Ulamog's Dreadsire's tap activation.
• The Thirteenth Doctor

  1GU

  Legendary Creature — Time Lord DoctorGU

  The Thirteenth Doctor untaps all (or many) permanents, refreshing Ulamog's Dreadsire's tap activation.
• Animate Dead

  1B

  Enchantment — AuraB

  Animate Dead puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Exhume

  1B

  SorceryB

  Exhume puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Hell's Caretaker

  3B

  Creature — HorrorB

  Hell's Caretaker puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Life // Death

  G1B

  Sorcery // SorceryBG

  Life puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Kardur's Vicious Return

  2BR

  Enchantment — SagaBR

  Kardur's Vicious Return puts Ulamog's Dreadsire 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 Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Meren of Clan Nel Toth

  2BG

  Legendary Creature — Human ShamanBG

  Meren of Clan Nel Toth puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Victimize

  2B

  SorceryB

  Victimize puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Persist

  1B

  SorceryB

  Persist puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Drumbellower

  2W

  Creature — SpiritW

  Drumbellower untaps all (or many) permanents, refreshing Ulamog's Dreadsire's tap activation.
• Plargg, Dean of Chaos // Augusta, Dean of Order

  1R2W

  Legendary Creature — Orc Shaman // Legendary Creature — Human ClericRW

  Plargg, Dean of Chaos untaps all (or many) permanents, refreshing Ulamog's Dreadsire's tap activation.
• Soul Exchange

  BB

  SorceryB

  Soul Exchange puts Ulamog's Dreadsire onto the battlefield from a graveyard without casting it, so its mana cost is never paid.