Lullmage Mentor

Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.
Tap seven untapped Merfolk you control: Counter target spell.

Disruptive Student

{T}: Counter target spell unless its controller pays {1}.

Vodalian Mage

{U}, {T}: Counter target spell unless its controller pays {1}.

Benevolent Geist

Flying
Noncreature spells you control can't be countered.
If Benevolent Geist would be put into a graveyard from anywhere, exile it instead.

Malevolent Hermit

{U}, Sacrifice Malevolent Hermit: Counter target noncreature spell unless its controller pays {3}.
Disturb {2}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Malevolent Hermit // Benevolent Geist

Mundungu

{T}: Counter target spell unless its controller pays {1} and 1 life.

Order of the Sacred Torch

{T}, Pay 1 life: Counter target black spell.

Ertai, the Corrupted

{U}, {T}, Sacrifice a creature or enchantment: Counter target spell.

Counterlash

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

Disruptive Pitmage

{T}: Counter target spell unless its controller pays {1}.
Morph {U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Cursecatcher

Sacrifice Cursecatcher: Counter target instant or sorcery spell unless its controller pays {1}.

Presence of the Master

Whenever a player casts an enchantment spell, counter it.

Lifeforce

Judge's Familiar

Flying
Sacrifice Judge's Familiar: Counter target instant or sorcery spell unless its controller pays {1}.

Stronghold Machinist

{U}{U}, {T}, Discard a card: Counter target noncreature spell.

Declaration of Naught

As Declaration of Naught enters, choose a card name.
{U}: Counter target spell with the chosen name.

Kozilek, the Great Distortion

When you cast this spell, if you have fewer than seven cards in hand, draw cards equal to the difference.
Menace
Discard a card with mana value X: Counter target spell with mana value X.

Stronghold Biologist

{U}{U}, {T}, Discard a card: Counter target creature spell.

Ayesha Tanaka

Banding (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)
{T}: Counter target activated ability from an artifact source unless that ability's controller pays {W}. (Mana abilities can't be targeted.)

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.

Decree of Silence

Whenever an opponent casts a spell, counter that spell and put a depletion counter on Decree of Silence. If there are three or more depletion counters on Decree of Silence, sacrifice it.
Cycling {4}{U}{U} ({4}{U}{U}, Discard this card: Draw a card.)
When you cycle Decree of Silence, you may counter target spell.

Douse

Flash Counter

Tidal Control

Cumulative upkeep {2} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Pay 2 life or {2}: Counter target red or green spell. Any player may activate this ability.

Disciple of the Ring

{1}, Exile an instant or sorcery card from your graveyard: Choose one —
• Counter target noncreature spell unless its controller pays {2}.
• Disciple of the Ring gets +1/+1 until end of turn.
• Tap target creature.
• Untap target creature.

Thrull Wizard

{1}{B}: Counter target black spell unless that spell's controller pays {B} or {3}.

Deathgrip

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.")

Stromgald Cabal

{T}, Pay 1 life: Counter target white spell.

Mystic Snake

Flash
When Mystic Snake enters, counter target spell.

Solemnity

Players can't get counters.
Counters can't be put on artifacts, creatures, enchantments, or lands.

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.

Talrand, Sky Summoner

Whenever you cast an instant or sorcery spell, create a 2/2 blue Drake creature token with flying.

Counterspell

Kheru Spellsnatcher

Morph {4}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Kheru Spellsnatcher is turned face up, counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard. You may cast that card without paying its mana cost for as long as it remains exiled.

Sunken Field

Enchant land
Enchanted land has "{T}: Counter target spell unless its controller pays {1}."

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.)