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.)

Talisman of Curiosity

{T}: Add {C}.
{T}: Add {G} or {U}. Talisman of Curiosity deals 1 damage to you.

Phantom Interference

Spree (Choose one or more additional costs.)
+ {3} — Create a 2/2 white Spirit creature token with flying.
+ {1} — Counter target spell unless its controller pays {2}.

Rite of Flame

Add {R}{R}, then add {R} for each card named Rite of Flame in each graveyard.

Neoform

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a creature card with mana value equal to 1 plus the sacrificed creature's mana value, put that card onto the battlefield with an additional +1/+1 counter on it, then shuffle.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Guttural Response

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Admiral's Order

Raid — If you attacked this turn, you may pay {U} rather than pay this spell's mana cost.
Counter target spell.

Mental Misstep

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

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Noxious Revival

({G/P} can be paid with either {G} or 2 life.)
Put target card from a graveyard on top of its owner's library.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Snap

Return target creature to its owner's hand. Untap up to two lands.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Disrupt

Counter target instant or sorcery spell unless its controller pays {1}.
Draw a card.

Strix Serenade

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

Sol Ring

Enter the Enigma

Target creature can't be blocked this turn.
Draw a card.

Birds of Paradise

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.

Storm, Force of Nature

Flying, vigilance
Ceaseless Tempest — Whenever Storm deals combat damage to a player, the next instant or sorcery spell you cast this turn has storm. (When you cast it, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Decisive Denial

Choose one —
• Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)
• Counter target noncreature spell unless its controller pays {3}.

Spell Pierce

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

Elvish Spirit Guide

Exile Elvish Spirit Guide from your hand: Add {G}.

Miscast

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

Dispel

Veil of Summer

Draw a card if an opponent has cast a blue or black spell this turn. Spells you control can't be countered this turn. You and permanents you control gain hexproof from blue and from black until end of turn. (You and they can't be the targets of blue or black spells or abilities your opponents control.)

Borne Upon a Wind

You may cast spells this turn as though they had flash.
Draw a card.

An Offer You Can't Refuse

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

Disrupting Shoal

You may exile a blue card with mana value X from your hand rather than pay this spell's mana cost.
Counter target spell if its mana value is X.

Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

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.)