Counterbore

Counter target spell. Search its controller's graveyard, hand, and library for all cards with the same name as that spell and exile them. Then that player shuffles.

Counterbalance

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, counter that spell if it has the same mana value as the revealed card.

Counterlash

Counter target spell. You may cast a spell that shares a card type with it from your hand without paying its mana cost.

Burnout

Counter target instant spell if it's blue.
Draw a card at the beginning of the next turn's upkeep.

Abjure

As an additional cost to cast this spell, sacrifice a blue permanent.
Counter target spell.

Countersquall

Counter target noncreature spell. Its controller loses 2 life.

Admiral's Order

Raid — If you attacked this turn, you may pay {U} rather than pay this spell's mana cost.
Counter target spell.

Abstruse Interference

Devoid (This card has no color.)
Counter target spell unless its controller pays {1}. You create a 1/1 colorless Eldrazi Scion creature token. It has "Sacrifice this creature: Add {C}." ({C} represents colorless mana.)

Ceremonious Rejection

Dispel

Contradict

Glen Elendra Archmage

Flying
{U}, Sacrifice Glen Elendra Archmage: Counter target noncreature spell.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Clash of Wills

Counter target spell unless its controller pays {X}.

Brine Seer

{2}{U}, {T}: Reveal any number of blue cards in your hand. Counter target spell unless its controller pays {1} for each card revealed this way.

Complicate

Counter target spell unless its controller pays {3}.
Cycling {2}{U} ({2}{U}, Discard this card: Draw a card.)
When you cycle Complicate, you may counter target spell unless its controller pays {1}.

Countermand

Counter target spell. Its controller mills four cards.

Avoid Fate

Counter target instant or Aura spell that targets a permanent you control.

Counterspell

Confirm Suspicions

Counter target spell.
Investigate three times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Cancel

Flash Counter

Countervailing Winds

Counter target spell unless its controller pays {1} for each card in your graveyard.
Cycling {2} ({2}, Discard this card: Draw a card.)

Broken Concentration

Counter target spell.
Madness {3}{U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

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 the top or bottom. A player wins if their card had a higher mana value.)

Jaraku the Interloper

Remove a ki counter from Jaraku the Interloper: Counter target spell unless its controller pays {2}.

Callow Jushi

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on Callow Jushi.
At the beginning of the end step, if there are two or more ki counters on Callow Jushi, you may flip it.

Callow Jushi // Jaraku the Interloper

Convolute

Counter target spell unless its controller pays {4}.

Artifact Blast

Assert Authority

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Autumn's Veil

Spells you control can't be countered by blue or black spells this turn, and creatures you control can't be the targets of blue or black spells this turn.

Archmage's Charm

Choose one —
• Counter target spell.
• Target player draws two cards.
• Gain control of target nonland permanent with mana value 1 or less.

Blue Elemental Blast

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

Cerulean Drake

Flying
Protection from red (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything red.)
Sacrifice Cerulean Drake: Counter target spell that targets you.

Controvert

Counter target spell.
Recover {2}{U}{U} (When a creature is put into your graveyard from the battlefield, you may pay {2}{U}{U}. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Confound

Counter target spell that targets a creature.
Draw a card.

Arenson's Aura

{W}, Sacrifice an enchantment: Destroy target enchantment.
{3}{U}{U}: Counter target enchantment spell.

Bone to Ash

Counter target creature spell.
Draw a card.

Corrupted Resolve

Counter target spell if its controller is poisoned.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Counterflux

This spell can't be countered.
Counter target spell you don't control.
Overload {1}{U}{U}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Circular Logic

Counter target spell unless its controller pays {1} for each card in your graveyard.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Brine Shaman

{T}, Sacrifice a creature: Target creature gets +2/+2 until end of turn.
{1}{U}{U}, Sacrifice a creature: Counter target creature spell.

Calculated Dismissal

Counter target spell unless its controller pays {3}.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, scry 2. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Bant Charm

Choose one —
• Destroy target artifact.
• Put target creature on the bottom of its owner's library.
• Counter target instant spell.

Annul

Counter target artifact or enchantment spell.

Condescend

Counter target spell unless its controller pays {X}. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Absorb

Censor

Counter target spell unless its controller pays {1}.
Cycling {U} ({U}, Discard this card: Draw a card.)