Guttersnipe

Whenever you cast an instant or sorcery spell, Guttersnipe deals 2 damage to each opponent.

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

Nivmagus Elemental

Exile an instant or sorcery spell you control: Put two +1/+1 counters on Nivmagus Elemental. (That spell won't resolve.)

Think Twice

Draw a card.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Shock

Syncopate

Counter target spell unless its controller pays {X}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Dangerous

All creatures able to block target creature this turn do so.
Fuse (You may cast one or both halves of this card from your hand.)

Armed

Target creature gets +1/+1 and gains double strike until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

Armed // Dangerous

Mountain

Izzet Guildgate

Izzet Guildgate enters the battlefield tapped.
{T}: Add {U} or {R}.

Hands of Binding

Tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Nivix Cyclops

Defender
Whenever you cast an instant or sorcery spell, Nivix Cyclops gets +3/+0 until end of turn and can attack this turn as though it didn't have defender.

Artful Dodge

Target creature can't be blocked this turn.
Flashback {U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Island

Hidden Strings

You may tap or untap target permanent, then you may tap or untap another target permanent.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Mizzium Skin

Target creature you control gets +0/+1 and gains hexproof until end of turn.
Overload {1}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")