Annul

Counter target artifact or enchantment spell.

Assimilate Essence

Counter target creature or battle spell unless its controller pays {4}. If they do, you incubate 2. (Create an Incubator token with two +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)

Clash of Wills

Counter target spell unless its controller pays {X}.

Disruption Protocol

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

Disdainful Stroke

Counter target spell with mana value 4 or greater.

Negate

Foil

You may discard an Island card and another card rather than pay this spell's mana cost.
Counter target spell.

Change the Equation

Choose one —
• Counter target spell with mana value 2 or less.
• Counter target red or green spell with mana value 6 or less.

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.")

Counterspell

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

Ertai's Scorn

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

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.)