Mental Misstep

({U/P} can be paid with either {U} or 2 life.)
Counter target spell with mana value 1.

Syncopate

Counter target spell unless its controller pays {X}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Frilled Mystic

Flash
When Frilled Mystic enters, you may counter target spell.

Ertai, Wizard Adept

Out of the Way

This spell costs {2} less to cast if it targets a green permanent.
Return target nonland permanent an opponent controls to its owner's hand.
Draw a card.

Negate

Convolute

Counter target spell unless its controller pays {4}.

Laquatus's Disdain

Counter target spell cast from a graveyard.
Draw a 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.

Counterspell

Steel Sabotage

Choose one —
• Counter target artifact spell.
• Return target artifact to its owner's hand.

Stifle

Counter target activated or triggered ability. (Mana abilities can't be targeted.)

Split the Party

Choose target player. Return half the creatures they control to their owner's hand, rounded up.

Absorb

Censor

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

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Jwari Ruins

Jwari Disruption

Counter target spell unless its controller pays {1}.

Jwari Disruption // Jwari Ruins

Jace's Defeat

Counter target blue spell. If it was a Jace planeswalker spell, scry 2.

Haughty Djinn

Flying
Haughty Djinn's power is equal to the number of instant and sorcery cards in your graveyard.
Instant and sorcery spells you cast cost {1} less to cast.

Disallow

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Didn't Say Please

Counter target spell. Its controller mills three cards.

Miscast

Counter target instant or sorcery spell unless its controller pays {3}.

Disrupt

Counter target instant or sorcery spell unless its controller pays {1}.
Draw a card.

Tale's End

Counter target activated ability, triggered ability, or legendary spell.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Remand

Counter target spell. If that spell is countered this way, put it into its owner's hand instead of into that player's graveyard.
Draw a card.

Denied!

Choose a card name, then target spell's controller reveals their hand. If a card with the chosen name is revealed this way, counter that spell.

Disdainful Stroke

Counter target spell with mana value 4 or greater.

Flash Counter

Vesuvan Duplimancy

Whenever you cast a spell that targets only a single artifact or creature you control, create a token that's a copy of that artifact or creature, except it's not legendary.

Protocol Knight

When Protocol Knight enters, tap target creature an opponent controls. Put a stun counter on that creature if you control another Knight. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Anticognition

Counter target creature or planeswalker spell unless its controller pays {2}. If an opponent has eight or more cards in their graveyard, instead counter that spell, then scry 2.

Bilbo, Retired Burglar

When Bilbo, Retired Burglar enters or leaves the battlefield, the Ring tempts you.
Whenever Bilbo deals combat damage to a player, create a Treasure token.

Punish Ignorance

Counter target spell. Its controller loses 3 life and you gain 3 life.

Snap

Return target creature to its owner's hand. Untap up to two lands.

Saiba Cryptomancer

Flash
Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
Hexproof

Saw It Coming

Counter target spell.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Psychic Rebuttal

Counter target instant or sorcery spell that targets you.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, you may copy the spell countered this way. You may choose new targets for the copy.

Dismiss

Kasmina's Transmutation

Enchant creature
Enchanted creature loses all abilities and has base power and toughness 1/1.

Override

Counter target spell unless its controller pays {1} for each artifact you control.

Annul

Counter target artifact or enchantment spell.

Spell Blast

Counter target spell with mana value X. (For example, if that spell's mana cost is {3}{U}{U}, X is 5.)

Fervent Denial

Counter target spell.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Gainsay

Ertai's Scorn

This spell costs {U} less to cast if an opponent cast two or more spells this turn.
Counter target spell.

Exclude

Counter target creature spell.
Draw a card.

Jaded Response

Counter target spell if it shares a color with a creature you control.

Vedalken Humiliator

Metalcraft — Whenever Vedalken Humiliator attacks, if you control three or more artifacts, creatures your opponents control lose all abilities and have base power and toughness 1/1 until end of turn.

Rewind

Counter target spell. Untap up to four lands.

Thought Collapse

Force Spike

Dispersal Shield

Counter target spell if its mana value is less than or equal to the highest mana value among permanents you control.

Logic Knot

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Counter target spell unless its controller pays {X}.

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.)

Rethink

Counter target spell unless its controller pays {X}, where X is its mana value.

Ray of Command

Untap target creature an opponent controls and gain control of it until end of turn. That creature gains haste until end of turn. When you lose control of the creature, tap it.

Second Guess

Counter target spell that's the second spell cast this turn.

Decisive Denial

Choose one —
• Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)
• Counter target noncreature spell unless its controller pays {3}.

Schema Thief

Flying
Whenever Schema Thief deals combat damage to a player, create a token that's a copy of target artifact that player controls.

Mystical Dispute

This spell costs {2} less to cast if it targets a blue spell.
Counter target spell unless its controller pays {3}.

Flaccify

Counter target spell unless its controller pays {3}{½}.

Unified Will

Counter target spell if you control more creatures than that spell's controller.

Flashfreeze

Disruption Protocol

As an additional cost to cast this spell, tap an untapped artifact you control or pay {1}.
Counter target spell.

Last Word

This spell can't be countered.
Counter target spell.

Reject Imperfection

Counter target spell. If that spell's mana value was 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)