Web of Inertia

At the beginning of combat on each opponent's turn, that player may exile a card from their graveyard. If the player doesn't, creatures they control can't attack you this turn.

Counterspell

Grip of Amnesia

Counter target spell unless its controller exiles all cards from their graveyard.
Draw a card.

Soul Barrier

Whenever an opponent casts a creature spell, Soul Barrier deals 2 damage to that player unless they pay {2}.

Mind Games

Buyback {2}{U} (You may pay an additional {2}{U} as you cast this spell. If you do, put this card into your hand as it resolves.)
Tap target artifact, creature, or land.

Telepathy

Your opponents play with their hands revealed.

Divert

Change the target of target spell with a single target unless that spell's controller pays {2}.

Hesitation

When a player casts a spell, sacrifice Hesitation and counter that spell.

Catalog

Errant Minion

Enchant creature
At the beginning of the upkeep of enchanted creature's controller, that player may pay any amount of mana. Errant Minion deals 2 damage to that player. Prevent X of that damage, where X is the amount of mana that player paid this way.

Slow Motion

Enchant creature
At the beginning of the upkeep of enchanted creature's controller, that player sacrifices that creature unless they pay {2}.
When Slow Motion is put into a graveyard from the battlefield, return Slow Motion to its owner's hand.

Island

Cognivore

Flying
Cognivore's power and toughness are each equal to the number of instant cards in all graveyards.

Opportunity

Voidmage Apprentice

Morph {2}{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 Voidmage Apprentice is turned face up, counter target spell.

Mana Leak

Counter target spell unless its controller pays {3}.

Invoke Prejudice

Whenever an opponent casts a creature spell that doesn't share a color with a creature you control, counter that spell unless that player pays {X}, where X is its mana value.

Capsize

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Return target permanent to its owner's hand.

Deflection

Change the target of target spell with a single target.

Willbender

Morph {1}{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 Willbender is turned face up, change the target of target spell or ability with a single target.

Standstill

When a player casts a spell, sacrifice Standstill. If you do, each of that player's opponents draws three cards.