Combust

This spell can't be countered.
Combust deals 5 damage to target white or blue creature. The damage can't be prevented.

Riverfall Mimic

Whenever you cast a spell that's both blue and red, Riverfall Mimic has base power and toughness 3/3 until end of turn and can't be blocked this turn.

Spell Rupture

Counter target spell unless its controller pays {X}, where X is the greatest power among creatures you control.

Clout of the Dominus

Enchant creature
As long as enchanted creature is blue, it gets +1/+1 and has shroud. (It can't be the target of spells or abilities.)
As long as enchanted creature is red, it gets +1/+1 and has haste.

Mindswipe

Counter target spell unless its controller pays {X}. Mindswipe deals X damage to that spell's controller.

Aetherize

Return all attacking creatures to their owner's hand.

Essence Backlash

Counter target creature spell. Essence Backlash deals damage equal to that spell's power to its controller.

Heat Ray

Heat Ray deals X damage to target creature.

Island

Quash

Counter target instant or sorcery spell. Search its controller's graveyard, hand, and library for all cards with the same name as that spell and exile them. Then that player shuffles.

Serum Sovereign

Flying
Whenever you cast a noncreature spell, put an oil counter on Serum Sovereign.
{U}, Remove an oil counter from Serum Sovereign: Draw a card, then scry 2.

Izzet Guildgate

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

Blistercoil Weird

Whenever you cast an instant or sorcery spell, Blistercoil Weird gets +1/+1 until end of turn. Untap it.

Invade the City

Amass Zombies X, where X is the number of instant and sorcery cards in your graveyard. (Put X +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)

Lose Focus

Replicate {U} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)
Counter target spell unless its controller pays {2}.

Nucklavee

When Nucklavee enters, you may return target red sorcery card from your graveyard to your hand.
When Nucklavee enters, you may return target blue instant card from your graveyard to your hand.

Mountain

Torch Breath

This spell costs {2} less to cast if it targets a blue permanent.
This spell can't be countered.
Torch Breath deals X damage to target creature or planeswalker.

Titan's Strength

Target creature gets +3/+1 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Spite of Mogis

Spite of Mogis deals damage to target creature equal to the number of instant and sorcery cards in your graveyard. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Sphinx of the Final Word

This spell can't be countered.
Flying, hexproof
Instant and sorcery spells you control can't be countered.

Spellheart Chimera

Flying, trample
Spellheart Chimera's power is equal to the number of instant and sorcery cards in your graveyard.

Keep Safe

Counter target spell that targets a permanent you control.
Draw a card.

Pore Over the Pages

Draw three cards, untap up to two lands, then discard a card.

Clash of Wills

Counter target spell unless its controller pays {X}.

Jwari Ruins

Jwari Disruption

Counter target spell unless its controller pays {1}.

Jwari Disruption // Jwari Ruins

Thunderous Wrath

Thunderous Wrath deals 5 damage to any target.
Miracle {R} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Glint

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Chandra's Phoenix

Flying
Haste (This creature can attack and {T} as soon as it comes under your control.)
Whenever an opponent is dealt damage by a red instant or sorcery spell you control or by a red planeswalker you control, return Chandra's Phoenix from your graveyard to your hand.