Confidence:StrongSolidPlausibleTentativeSpeculative

• Intellectual Offering

  4U

  InstantU

  Intellectual Offering untaps all (or many) permanents, refreshing Shriekhorn's tap activation.
• Unstoppable Plan

  2U

  EnchantmentU

  Unstoppable Plan untaps all (or many) permanents, refreshing Shriekhorn's tap activation.
• Unwinding Clock

  4

  ArtifactC

  Unwinding Clock untaps all (or many) permanents, refreshing Shriekhorn's tap activation.
• Seedborn Muse

  3GG

  Creature — SpiritG

  Seedborn Muse untaps all (or many) permanents, refreshing Shriekhorn's tap activation.
• Innkeeper's Talent

  1G

  Enchantment — ClassG

  Counter synergy: both cards work with the same kind of counters, so their effects stack in a counters deck. Not necessarily a closed loop on its own.
• Paradox Engine

  5

  Legendary ArtifactC

  Paradox Engine untaps all (or many) permanents, refreshing Shriekhorn's tap activation.
• Dramatic Reversal

  1U

  InstantU

  Dramatic Reversal untaps all (or many) permanents, refreshing Shriekhorn's tap activation.
• Blinkmoth Infusion

  12UU

  InstantU

  Blinkmoth Infusion untaps all (or many) permanents, refreshing Shriekhorn's tap activation.
• The Haunt of Hightower

  4BB

  Legendary Creature — VampireB

  Shriekhorn mills (or dredges) cards into your graveyard, and The Haunt of Hightower pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Bloodchief Ascension

  B

  EnchantmentB

  Shriekhorn mills (or dredges) cards into your graveyard, and Bloodchief Ascension pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Vulturous Zombie

  3BG

  Creature — Plant ZombieBG

  Shriekhorn mills (or dredges) cards into your graveyard, and Vulturous Zombie pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Quest for Ancient Secrets

  U

  EnchantmentU

  Shriekhorn mills (or dredges) cards into your graveyard, and Quest for Ancient Secrets pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Nihilith

  4BB

  Creature — HorrorB

  Shriekhorn mills (or dredges) cards into your graveyard, and Nihilith pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Sefris of the Hidden Ways

  WUB

  Legendary Creature — Human WizardBUW

  Shriekhorn mills (or dredges) cards into your graveyard, and Sefris of the Hidden Ways pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Dennick, Pious Apprentice // Dennick, Pious Apparition

  WU

  Legendary Creature — Human Soldier // Legendary Creature — Spirit SoldierUW

  Shriekhorn mills (or dredges) cards into your graveyard, and Dennick, Pious Apprentice pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Sand Scout

  1W

  Creature — Human ScoutW

  Shriekhorn mills (or dredges) cards into your graveyard, and Sand Scout pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Titania, Voice of Gaea

  1GG

  Legendary Creature — ElementalG

  Shriekhorn mills (or dredges) cards into your graveyard, and Titania, Voice of Gaea pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Robot Domination

  3B

  Enchantment — PlanB

  Shriekhorn mills (or dredges) cards into your graveyard, and Robot Domination pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Slogurk, the Overslime

  1GU

  Legendary Creature — OozeGU

  Shriekhorn mills (or dredges) cards into your graveyard, and Slogurk, the Overslime pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• The Gitrog Monster

  3BG

  Legendary Creature — Frog HorrorBG

  Shriekhorn mills (or dredges) cards into your graveyard, and The Gitrog Monster pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Voracious Brood

  2G

  Creature — Alien InsectG

  Shriekhorn mills (or dredges) cards into your graveyard, and Voracious Brood pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Lazav, Dimir Mastermind

  UUBB

  Legendary Creature — ShapeshifterBU

  Shriekhorn mills (or dredges) cards into your graveyard, and Lazav, Dimir Mastermind pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Turntimber Sower

  2G

  Creature — Elf DruidG

  Shriekhorn mills (or dredges) cards into your graveyard, and Turntimber Sower pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Compost

  1G

  EnchantmentG

  Shriekhorn mills (or dredges) cards into your graveyard, and Compost pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.
• Countryside Crusher

  1RR

  Creature — Giant WarriorR

  Shriekhorn mills (or dredges) cards into your graveyard, and Countryside Crusher pays off whenever a card — or a card of the type it names — is put into a graveyard from anywhere; the more it mills, the likelier it hits.