Artifact Blast

Withering Boon

As an additional cost to cast this spell, pay 3 life.
Counter target creature spell.

Nullstone Gargoyle

Flying
Whenever the first noncreature spell of a turn is cast, counter that spell.

Stromgald Cabal

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

Dawn Charm

Choose one —
• Prevent all combat damage that would be dealt this turn.
• Regenerate target creature.
• Counter target spell that targets you.

Null Brooch

{2}, {T}, Discard your hand: Counter target noncreature spell.

Ring of Immortals

{3}, {T}: Counter target instant or Aura spell that targets a permanent you control.

Bruse Tarl, Boorish Herder

Whenever Bruse Tarl, Boorish Herder enters or attacks, target creature you control gains double strike and lifelink until end of turn.
Partner (You can have two commanders if both have partner.)

Amulet of Safekeeping

Whenever you become the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.
Creature tokens get -1/-0.

Rebuff the Wicked

Counter target spell that targets a permanent you control.

Lapse of Certainty

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Nether Void

Whenever a player casts a spell, counter it unless that player pays {3}.

Frontline Medic

Battalion — Whenever Frontline Medic and at least two other creatures attack, creatures you control gain indestructible until end of turn.
Sacrifice Frontline Medic: Counter target spell with {X} in its mana cost unless its controller pays {3}.

Lifeforce

Deathgrip

Burnout

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

Red Elemental Blast

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

Chancellor of the Annex

You may reveal this card from your opening hand. If you do, when each opponent casts their first spell of the game, counter that spell unless that player pays {1}.
Flying
Whenever an opponent casts a spell, counter it unless that player pays {1}.

Mages' Contest

You and target spell's controller bid life. You start the bidding with a bid of 1. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid. If you win the bidding, counter that spell.

Guttural Response

Not of This World

Counter target spell or ability that targets a permanent you control.
This spell costs {7} less to cast if it targets a spell or ability that targets a creature you control with power 7 or greater.

Molten Influence

Counter target instant or sorcery spell unless its controller has Molten Influence deal 4 damage to them.

Avoid Fate

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

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.

Presence of the Master

Whenever a player casts an enchantment spell, counter it.

Warping Wail

({C} represents colorless mana.)
Choose one —
• Exile target creature with power or toughness 1 or less.
• Counter target sorcery spell.
• Create a 1/1 colorless Eldrazi Scion creature token. It has "Sacrifice this creature: Add {C}."

Unyaro Griffin

Flying
Sacrifice Unyaro Griffin: Counter target red instant or sorcery spell.

Vigilant Martyr

Sacrifice Vigilant Martyr: Regenerate target creature.
{W}{W}, {T}, Sacrifice Vigilant Martyr: Counter target spell that targets an enchantment.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Order of the Sacred Torch

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

Planar Chaos

At the beginning of your upkeep, flip a coin. If you lose the flip, sacrifice Planar Chaos.
Whenever a player casts a spell, that player flips a coin. If they lose the flip, counter that spell.

Illumination

Counter target artifact or enchantment spell. Its controller gains life equal to its mana value.

Mana Tithe

Counter target spell unless its controller pays {1}.

Dash Hopes

When you cast this spell, any player may pay 5 life. If a player does, counter Dash Hopes.
Counter target spell.

Ikra Shidiqi, the Usurper

Menace
Whenever a creature you control deals combat damage to a player, you gain life equal to that creature's toughness.
Partner (You can have two commanders if both have partner.)

Equinox

Enchant land
Enchanted land has "{T}: Counter target spell if it would destroy a land you control."

Chalice of the Void

Chalice of the Void enters with X charge counters on it.
Whenever a player casts a spell with mana value equal to the number of charge counters on Chalice of the Void, counter that spell.

Reality Smasher

({C} represents colorless mana.)
Trample, haste
Whenever Reality Smasher becomes the target of a spell an opponent controls, counter that spell unless its controller discards a card.

Thrull Wizard

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