Simian Spirit Guide

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

Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Sol Ring

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Conjurer's Bauble

{T}, Sacrifice Conjurer's Bauble: Put up to one target card from your graveyard on the bottom of your library. Draw a card.

Impact Tremors

Whenever a creature enters the battlefield under your control, Impact Tremors deals 1 damage to each opponent.

Warlord's Fury

Creatures you control gain first strike until end of turn.
Draw a card.

Mizzix's Mastery

Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery.
Overload {5}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Guttersnipe

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

Helm of Awakening

Wild Guess

As an additional cost to cast this spell, discard a card.
Draw two cards.

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.)

Past in Flames

Each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Bag of Holding

Whenever you discard a card, exile that card from your graveyard.
{2}, {T}: Draw a card, then discard a card.
{4}, {T}, Sacrifice Bag of Holding: Return all cards exiled with Bag of Holding to their owner's hand.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Ignite Memories

Target player reveals a card at random from their hand. Ignite Memories deals damage to that player equal to that card's mana value.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Light Up the Stage

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Grinning Ignus

{R}, Return Grinning Ignus to its owner's hand: Add {C}{C}{R}. Activate only as a sorcery.

Kessig Flamebreather

Whenever you cast a noncreature spell, Kessig Flamebreather deals 1 damage to each opponent.

Priest of Urabrask

When Priest of Urabrask enters the battlefield, add {R}{R}{R}.

Comet Storm

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose any target, then choose another target for each time this spell was kicked. Comet Storm deals X damage to each of them.

Hazoret's Monument

Red creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, you may discard a card. If you do, draw a card.

Magus of the Wheel

{1}{R}, {T}, Sacrifice Magus of the Wheel: Each player discards their hand, then draws seven cards.

Mechanized Warfare

If a red or artifact source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 1 instead.

Mountain

Iron Myr

Thrill of Possibility

Cathartic Reunion

As an additional cost to cast this spell, discard two cards.
Draw three cards.

Tormenting Voice

Vessel of Volatility

{1}{R}, Sacrifice Vessel of Volatility: Add {R}{R}{R}{R}.

Magmatic Insight

As an additional cost to cast this spell, discard a land card.
Draw two cards.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Torbran, Thane of Red Fell

If a red source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

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.)

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Bedlam Reveler

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Prowess
When Bedlam Reveler enters the battlefield, discard your hand, then draw three cards.

Reinforced Ronin

Haste
At the beginning of your end step, return Reinforced Ronin to its owner's hand.
Channel — {1}{R}, Discard Reinforced Ronin: Draw a card.

Zada, Hedron Grinder

Whenever you cast an instant or sorcery spell that targets only Zada, Hedron Grinder, copy that spell for each other creature you control that the spell could target. Each copy targets a different one of those creatures.

Conspiracy Theorist

Whenever Conspiracy Theorist attacks, you may pay {1} and discard a card. If you do, draw a card.
Whenever you discard one or more nonland cards, you may exile one of them from your graveyard. If you do, you may cast it this turn.

Fire Diamond

Fire Diamond enters the battlefield tapped.
{T}: Add {R}.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Containment Construct

Whenever you discard a card, you may exile that card from your graveyard. If you do, you may play that card this turn.

Backdraft Hellkite

Flying
Whenever Backdraft Hellkite attacks, each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.

Wrenn's Resolve

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

Renegade Tactics

Target creature can't block this turn.
Draw a card.

Haggle

You may discard a card. If you do, draw a card. (Then exile this card. You may cast the creature later from exile.)

Merchant of the Vale

Merchant of the Vale // Haggle

Ancestral Anger

Target creature gains trample and gets +X/+0 until end of turn, where X is 1 plus the number of cards named Ancestral Anger in your graveyard.
Draw a card.

Firebrand Archer

Whenever you cast a noncreature spell, Firebrand Archer deals 1 damage to each opponent.

Mizzium Mortars

Mizzium Mortars deals 4 damage to target creature you don't control.
Overload {3}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Krark, the Thumbless

Whenever you cast an instant or sorcery spell, flip a coin. If you lose the flip, return that spell to its owner's hand. If you win the flip, copy that spell, and you may choose new targets for the copy.
Partner (You can have two commanders if both have partner.)

Rile

Rile deals 1 damage to target creature you control. That creature gains trample until end of turn.
Draw a card.

Thought Vessel

Expedite

Target creature gains haste until end of turn.
Draw a card.

Crash Through

Creatures you control gain trample until end of turn. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)
Draw a card.

Witty Roastmaster

Alliance — Whenever another creature enters the battlefield under your control, Witty Roastmaster deals 1 damage to each opponent.

Runaway Steam-Kin

Whenever you cast a red spell, if Runaway Steam-Kin has fewer than three +1/+1 counters on it, put a +1/+1 counter on Runaway Steam-Kin.
Remove three +1/+1 counters from Runaway Steam-Kin: Add {R}{R}{R}.

Experimental Synthesizer

When Experimental Synthesizer enters or leaves the battlefield, exile the top card of your library. Until end of turn, you may play that card.
{2}{R}, Sacrifice Experimental Synthesizer: Create a 2/2 white Samurai creature token with vigilance. Activate only as a sorcery.

Harnfel, Horn of Bounty

Discard a card: Exile the top two cards of your library. You may play those cards this turn.

Birgi, God of Storytelling

Whenever you cast a spell, add {R}. Until end of turn, you don't lose this mana as steps and phases end.
Creatures you control can boast twice during each of your turns rather than once.

Birgi, God of Storytelling // Harnfel, Horn of Bounty

Flamekin Harbinger

When Flamekin Harbinger enters the battlefield, you may search your library for an Elemental card, reveal it, then shuffle and put that card on top.

Mana Geyser

Add {R} for each tapped land your opponents control.

Myriad Landscape

Myriad Landscape enters the battlefield tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Overmaster

The next instant or sorcery spell you cast this turn can't be countered.
Draw a card.

Commune with Lava

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

Spikefield Cave

Spikefield Cave enters the battlefield tapped.
{T}: Add {R}.

Spikefield Hazard

Spikefield Hazard deals 1 damage to any target. If a permanent dealt damage this way would die this turn, exile it instead.

Spikefield Hazard // Spikefield Cave

Tectonic Reformation

Each land card in your hand has cycling {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Thermo-Alchemist

Defender
{T}: Thermo-Alchemist deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap Thermo-Alchemist.

Electrostatic Field

Defender
Whenever you cast an instant or sorcery spell, Electrostatic Field deals 1 damage to each opponent.

Cleansing Wildfire

Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.
Draw a card.

Increasing Vengeance

Copy target instant or sorcery spell you control. If this spell was cast from a graveyard, copy that spell twice instead. You may choose new targets for the copies.
Flashback {3}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)