Lutri, the Spellchaser

Companion — Each nonland card in your starting deck has a different name. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Flash
When Lutri, the Spellchaser enters, if you cast it, copy target instant or sorcery spell you control. You may choose new targets for the copy.

Steam Augury

Reveal the top five cards of your library and separate them into two piles. An opponent chooses one of those piles. Put that pile into your hand and the other into your graveyard.

Swiftwater Cliffs

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {R}.

Izzet Charm

Choose one —
• Counter target noncreature spell unless its controller pays {2}.
• Izzet Charm deals 2 damage to target creature.
• Draw two cards, then discard two cards.

Blistercoil Weird

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

Sprite Dragon

Flying, haste
Whenever you cast a noncreature spell, put a +1/+1 counter on Sprite Dragon.

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.

Suffocating Blast

Counter target spell and Suffocating Blast deals 3 damage to target creature.

Lore Drakkis

Mutate {U/R}{U/R} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, return target instant or sorcery card from your graveyard to your hand.

Nivmagus Elemental

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

Gelectrode

{T}: Gelectrode deals 1 damage to any target.
Whenever you cast an instant or sorcery spell, you may untap Gelectrode.

Spellheart Chimera

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

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.

Mountain

Shrewd Hatchling

Shrewd Hatchling enters with four -1/-1 counters on it.
{U/R}: Target creature can't block Shrewd Hatchling this turn.
Whenever you cast a blue spell, remove a -1/-1 counter from Shrewd Hatchling.
Whenever you cast a red spell, remove a -1/-1 counter from Shrewd Hatchling.

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.

Mirror Sheen

{1}{U/R}{U/R}: Copy target instant or sorcery spell that targets you. You may choose new targets for the copy.

Island

Swerve

Change the target of target spell with a single target.

Izzet Guildgate

This land enters tapped.
{T}: Add {U} or {R}.

Mindswipe

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

Essence Backlash

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