Confidence:StrongSolidPlausibleTentativeSpeculative

• Innocuous Researcher

  3G

  Creature — Centaur DetectiveG

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

  2R

  SorceryR

  Fiery Gambit untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Jorn, God of Winter // Kaldring, the Rimestaff

  2G1UB

  Legendary Snow Creature — God // Legendary Snow ArtifactBGU

  Jorn, God of Winter untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Prophet of Kruphix

  3GU

  Creature — Human WizardGU

  Prophet of Kruphix untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Bumi, Unleashed

  3RG

  Legendary Creature — Human Noble AllyGR

  Bumi, Unleashed untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Zacama, Primal Calamity

  6RGW

  Legendary Creature — Elder DinosaurGRW

  Zacama, Primal Calamity untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Seedborn Muse

  3GG

  Creature — SpiritG

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

  3G

  EnchantmentG

  Wilderness Reclamation untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Sword of Feast and Famine

  3

  Artifact — EquipmentC

  Sword of Feast and Famine untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Beledros Witherbloom

  5BG

  Legendary Creature — Elder DragonBG

  Beledros Witherbloom untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Nature's Will

  2GG

  EnchantmentG

  Nature's Will untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Awakening

  2GG

  EnchantmentG

  Awakening untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Reset

  UU

  InstantU

  Reset untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Rude Awakening

  4G

  SorceryG

  Rude Awakening untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Bear Umbra

  2GG

  Enchantment — AuraG

  Bear Umbra untaps all (or many) permanents, refreshing Caustic Tar's tap activation.
• Rings of Brighthearth

  3

  ArtifactC

  Caustic Tar has activated abilities that aren't mana abilities, fueling Rings of Brighthearth's activation-trigger.