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.)

Gut Shot

({R/P} can be paid with either {R} or 2 life.)
Gut Shot deals 1 damage to any target.

Tome Scour

Iceberg Cancrix

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

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Thought Scour

Target player mills two cards.
Draw a card.

Mind Sculpt

Winds of Rebuke

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

Tolarian Terror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)

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.)

Curfew

Each player returns a creature they control to its owner's hand.

Snow-Covered Island

Winter's Rest

Enchant creature
When this Aura enters, tap enchanted creature.
As long as you control another snow permanent, enchanted creature doesn't untap during its controller's untap step.

Jace's Phantasm

Flying
This creature gets +4/+4 as long as an opponent has ten or more cards in their graveyard.

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.)

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.