Confidence:StrongSolidPlausibleTentativeSpeculative

• Fiery Gambit

  2R

  SorceryR

  Fiery Gambit untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.
• Innocuous Researcher

  3G

  Creature — Centaur DetectiveG

  Innocuous Researcher untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.
• Oriq Loremage

  2BB

  Creature — Human WarlockB

  Oriq Loremage puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Buried Alive

  2B

  SorceryB

  Buried Alive puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Entomb

  B

  InstantB

  Entomb puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Cynical Loner

  1B

  Creature — Human SurvivorB

  Cynical Loner puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Final Parting

  3BB

  SorceryB

  Final Parting puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Beledros Witherbloom

  5BG

  Legendary Creature — Elder DragonBG

  Beledros Witherbloom untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.
• Saryth, the Viper's Fang

  2GG

  Legendary Creature — Human WarlockG

  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.
• Prophet of Kruphix

  3GU

  Creature — Human WizardGU

  Prophet of Kruphix untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.
• Unmarked Grave

  1B

  SorceryB

  Unmarked Grave puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Gravebreaker Lamia

  4B

  Enchantment Creature — Snake LamiaB

  Gravebreaker Lamia puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Bumi, Unleashed

  3RG

  Legendary Creature — Human Noble AllyGR

  Bumi, Unleashed untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.
• Vile Entomber

  2BB

  Creature — Zombie WarlockB

  Vile Entomber puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Jarad's Orders

  2BG

  SorceryBG

  Jarad's Orders puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Wilderness Reclamation

  3G

  EnchantmentG

  Wilderness Reclamation untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.
• Seedborn Muse

  3GG

  Creature — SpiritG

  Seedborn Muse untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.
• Dina's Guidance

  1BG

  InstantBG

  Dina's Guidance puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Lively Dirge

  1B

  SorceryB

  Lively Dirge puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Sword of Feast and Famine

  3

  Artifact — EquipmentC

  Sword of Feast and Famine untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.
• Corpse Connoisseur

  4B

  Creature — Zombie WizardB

  Corpse Connoisseur puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Scion of the Ur-Dragon

  WUBRG

  Legendary Creature — Dragon AvatarBGRUW

  Scion of the Ur-Dragon puts a creature card from your library straight into your graveyard, and Havengul Laboratory returns it from there — onto the battlefield or to your hand.
• Nature's Will

  2GG

  EnchantmentG

  Nature's Will untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.
• Emrakul, the Exigent Doom

  10

  Legendary Creature — EldraziC

  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.
• Awakening

  2GG

  EnchantmentG

  Awakening untaps all (or many) permanents, refreshing Havengul Laboratory's tap activation.