Considering

Spark Spray

Spark Spray deals 1 damage to any target.
Cycling {R} ({R}, Discard this card: Draw a card.)

Fiery Impulse

Fiery Impulse deals 2 damage to target creature.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, Fiery Impulse deals 3 damage instead.

Fact or Fiction

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

Slice and Dice

Slice and Dice deals 4 damage to each creature.
Cycling {2}{R} ({2}{R}, Discard this card: Draw a card.)
When you cycle Slice and Dice, you may have it deal 1 damage to each creature.

Wrenn's Resolve

Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Ovinize

Until end of turn, target creature loses all abilities and has base power and toughness 0/1.

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Peregrine Drake

Flying
When Peregrine Drake enters the battlefield, untap up to five lands.

Fiery Temper

Fiery Temper deals 3 damage to any target.
Madness {R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Voltage Surge

As an additional cost to cast this spell, you may sacrifice an artifact.
Voltage Surge deals 2 damage to target creature or planeswalker. If this spell's additional cost was paid, Voltage Surge deals 4 damage instead.

Goblin Electromancer

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

Grapeshot

Grapeshot deals 1 damage to any target.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Inferno Titan

{R}: Inferno Titan gets +1/+0 until end of turn.
Whenever Inferno Titan enters the battlefield or attacks, it deals 3 damage divided as you choose among one, two, or three targets.

Akroan Horse

Defender
When Akroan Horse enters the battlefield, an opponent gains control of it.
At the beginning of your upkeep, each opponent creates a 1/1 white Soldier creature token.

Alchemist's Greeting

Alchemist's Greeting deals 4 damage to target creature.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Wizard's Retort

This spell costs {1} less to cast if you control a Wizard.
Counter target spell.

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Obsessive Search

Draw a card.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Shatter the Source

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Choose one —
• Shatter the Source deals 6 damage to target creature, planeswalker, or battle.
• Destroy target artifact.

Millikin

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Negate

Impulse

Look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Sorcerer's Wand

Equipped creature has "{T}: This creature deals 1 damage to target player or planeswalker. If this creature is a Wizard, it deals 2 damage instead."
Equip {3}

Aegar, the Freezing Flame

Whenever a creature or planeswalker an opponent controls is dealt excess damage, if a Giant, Wizard, or spell you controlled dealt damage to it this turn, draw a card.

Swiftwater Cliffs

Swiftwater Cliffs enters the battlefield tapped.
When Swiftwater Cliffs enters the battlefield, you gain 1 life.
{T}: Add {U} or {R}.

Wizard's Lightning

This spell costs {2} less to cast if you control a Wizard.
Wizard's Lightning deals 3 damage to any target.

Lightning Rift

Whenever a player cycles a card, you may pay {1}. If you do, Lightning Rift deals 2 damage to any target.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Breath Weapon

Breath Weapon deals 2 damage to each non-Dragon creature.

Smoldering Crater

Smoldering Crater enters the battlefield tapped.
{T}: Add {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Stoke the Flames

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Stoke the Flames deals 4 damage to any target.

Remote Isle

Remote Isle enters the battlefield tapped.
{T}: Add {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Fire

Fire deals 2 damage divided as you choose among one or two targets.

Fire // Ice

Empty the Warrens

Create two 1/1 red Goblin creature tokens.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Turnabout

Choose artifact, creature, or land. Tap all untapped permanents of the chosen type target player controls, or untap all tapped permanents of that type that player controls.

Disciples of the Inferno

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
If a noncreature source you control would deal damage to a creature, battle, or opponent, it deals that much damage plus 2 instead.

Invasion of Regatha

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Regatha enters the battlefield, it deals 4 damage to another target battle or opponent and 1 damage to up to one target creature.

Invasion of Regatha // Disciples of the Inferno

Solar Blast

Solar Blast deals 3 damage to any target.
Cycling {1}{R}{R} ({1}{R}{R}, Discard this card: Draw a card.)
When you cycle Solar Blast, you may have it deal 1 damage to any target.

Firefist Adept

When Firefist Adept enters the battlefield, it deals X damage to target creature an opponent controls, where X is the number of Wizards you control.

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.

Baral, Chief of Compliance

Instant and sorcery spells you cast cost {1} less to cast.
Whenever a spell or ability you control counters a spell, you may draw a card. If you do, discard a card.

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

Highland Lake

Highland Lake enters the battlefield tapped.
{T}: Add {U} or {R}.

Guttersnipe

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

Arcanis the Omnipotent

{T}: Draw three cards.
{2}{U}{U}: Return Arcanis the Omnipotent to its owner's hand.

Counterspell

Storm Entity

Haste
Storm Entity enters the battlefield with a +1/+1 counter on it for each other spell cast this turn.

Izzet Boilerworks

Izzet Boilerworks enters the battlefield tapped.
When Izzet Boilerworks enters the battlefield, return a land you control to its owner's hand.
{T}: Add {U}{R}.