Counterspell

Miscalculation

Counter target spell unless its controller pays {2}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Muddle the Mixture

Counter target instant or sorcery spell.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Dispel

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.

Flare of Denial

You may sacrifice a nontoken blue creature rather than pay this spell's mana cost.
Counter target spell.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Flusterstorm

Counter target instant or sorcery spell unless its controller pays {1}.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Spell Pierce

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

Consign to Memory

Replicate {1} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)
Counter target triggered ability or colorless spell.

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.

Delay

Counter target spell. If the spell is countered this way, exile it with three time counters on it instead of putting it into its owner's graveyard. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, they remove a time counter. When the last is removed, they may play it without paying its mana cost. If it's a creature, it has haste.)

Pact of Negation

Counter target spell.
At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.

Stifle

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

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Trickbind

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Counter target activated or triggered ability. If a permanent's ability is countered this way, activated abilities of that permanent can't be activated this turn. (Mana abilities can't be targeted.)

Stubborn Denial

Counter target noncreature spell unless its controller pays {1}.
Ferocious — If you control a creature with power 4 or greater, counter that spell instead.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Spell Snare

Mental Misstep

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

Miscast

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

Strix Serenade

Counter target artifact, creature, or planeswalker spell. Its controller creates a 2/2 blue Bird creature token with flying.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.