Stream of Thought

Target player mills four cards. You shuffle up to four cards from your graveyard into your library.
Replicate {2}{U}{U} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)

Iceberg Cancrix

Whenever another snow permanent you control enters, you may have target player mill two cards.

Thought Collapse

Counter target spell. Its controller mills three cards.

Thought Scour

Target player mills two cards.
Draw a card.

Dampen Thought

Target player mills four cards.
Splice onto Arcane {1}{U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Book Burning

Any player may have Book Burning deal 6 damage to them. If no one does, target player mills six cards.

Chronic Flooding

Enchant land
Whenever enchanted land becomes tapped, its controller mills three cards.

Broken Ambitions

Counter target spell unless its controller pays {X}. Clash with an opponent. If you win, that spell's controller mills four cards. (Each clashing player reveals the top card of their library, then puts that card on their choice of the top or bottom. A player wins if their card had a greater mana value.)

Merrow Witsniper

When this creature enters, target player mills a card.

Pilfered Plans

Target player mills two cards. Draw two cards.

Returned Reveler

When this creature dies, each player mills three cards.

Chilling Shade

Flying
{S}: This creature gets +1/+1 until end of turn. ({S} can be paid with one mana from a snow source.)

Dream Twist

Target player mills three cards.
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Mind Sculpt

Vision Charm

Choose one —
• Target player mills four cards.
• Choose a land type and a basic land type. Each land of the first chosen type becomes the second chosen type until end of turn.
• Target artifact phases out. (While it's phased out, it's treated as though it doesn't exist. It phases in before its controller untaps during their next untap step.)

Jace's Erasure

Whenever you draw a card, you may have target player mill a card.

Curse of the Bloody Tome

Enchant player
At the beginning of enchanted player's upkeep, that player mills two cards.

Winds of Rebuke

Return target nonland permanent to its owner's hand. Each player mills two cards.

Homarid Explorer

When this creature enters, target player mills four cards.

Thassa's Bounty

Draw three cards. Target player mills three cards.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Crosstown Courier

Whenever this creature deals combat damage to a player, that player mills that many cards.

Induce Paranoia

Counter target spell. If {B} was spent to cast this spell, that spell's controller mills X cards, where X is the spell's mana value.

Tome Scour

Psychic Strike

Counter target spell. Its controller mills two cards.

Balustrade Spy

Flying
When this creature enters, target player reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Merfolk Mesmerist

Island

Horrifying Revelation

Target player discards a card, then mills a card.

Countermand

Counter target spell. Its controller mills four cards.

Paranoid Delusions

Target player mills three cards.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Shriekhorn

This artifact enters with three charge counters on it.
{T}, Remove a charge counter from this artifact: Target player mills two cards.

Sage's Row Denizen

Whenever another blue creature you control enters, target player mills two cards.

Griptide

Put target creature on top of its owner's library.

Destroy the Evidence

Destroy target land. Its controller reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Deprive

As an additional cost to cast this spell, return a land you control to its owner's hand.
Counter target spell.

Swamp

Drowner Initiate

Whenever a player casts a blue spell, you may pay {1}. If you do, target player mills two cards.

Memory Lapse

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Shriekgeist

Flying
Whenever this creature deals combat damage to a player, that player mills two cards.

Dreadwaters

Target player mills X cards, where X is the number of lands you control.

Compelling Argument

Target player mills five cards.
Cycling {U} ({U}, Discard this card: Draw a card.)

Selhoff Occultist

Whenever this creature or another creature dies, target player mills a card.

Gelid Shackles

Enchant creature
Enchanted creature can't block, and its activated abilities can't be activated.
{S}: Enchanted creature gains defender until end of turn. ({S} can be paid with one mana from a snow source.)

Memory Sluice

Target player mills four cards.
Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)