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.)

Kari Zev's Expertise

Gain control of target creature or Vehicle until end of turn. Untap it. It gains haste until end of turn.
You may cast a spell with mana value 2 or less from your hand without paying its mana cost.

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.)

Expedite

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

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Renegade Tactics

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

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Samut's Sprint

Target creature gets +2/+1 and gains haste until end of turn. Scry 1.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Crimson Wisps

Target creature becomes red and gains haste until end of turn. (It can attack and {T} this turn.)
Draw a card.

Rograkh, Son of Rohgahh

First strike, menace, trample
Partner (You can have two commanders if both have partner.)

Kher Keep

{T}: Add {C}.
{1}{R}, {T}: Create a 0/1 red Kobold creature token named Kobolds of Kher Keep.

Temur Battle Rage

Target creature gains double strike until end of turn.
Ferocious — That creature also gains trample until end of turn if you control a creature with power 4 or greater.

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}.

Vandalblast

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

Tibalt's Trickery

Counter target spell. Choose 1, 2, or 3 at random. Its controller mills that many cards, then exiles cards from the top of their library until they exile a nonland card with a different name than that spell. They may cast that card without paying its mana cost. Then they put the exiled cards on the bottom of their library in a random order.

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Guttersnipe

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

Young Pyromancer

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

Goro-Goro, Disciple of Ryusei

{R}: Creatures you control gain haste until end of turn.
{3}{R}{R}: Create a 5/5 red Dragon Spirit creature token with flying. Activate only if you control an attacking modified creature. (Equipment, Auras you control, and counters are modifications.)

Dreadhorde Arcanist

Trample
Whenever Dreadhorde Arcanist attacks, you may cast target instant or sorcery card with mana value less than or equal to Dreadhorde Arcanist's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Accelerate

Chandra, Acolyte of Flame

0: Put a loyalty counter on each red planeswalker you control.
0: Create two 1/1 red Elemental creature tokens. They gain haste. Sacrifice them at the beginning of the next end step.
−2: You may cast target instant or sorcery card with mana value 3 or less from your graveyard. If that spell would be put into your graveyard, exile it instead.

Mountain

Dwarven Mine

({T}: Add {R}.)
Dwarven Mine enters tapped unless you control three or more other Mountains.
When Dwarven Mine enters untapped, create a 1/1 red Dwarf creature token.

Boiling Blood

Target creature attacks this turn if able.
Draw a card.

Stun

Ornithopter of Paradise

Beetleback Chief

When Beetleback Chief enters, create two 1/1 red Goblin creature tokens.

Spark of Creativity

Choose target creature. Exile the top card of your library. You may have Spark of Creativity deal damage to that creature equal to the exiled card's mana value. If you don't, you may play that card until end of turn.

Mana Geyser

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

Kick in the Door

Put a +1/+1 counter on target creature. That creature gains haste until end of turn and can't be blocked by Walls this turn. Venture into the dungeon. (Enter the first room or advance to the next room.)

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. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)
Draw a card.

Thought Vessel

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

Underworld Breach

Each nonland card in your graveyard has escape. The escape cost is equal to the card's mana cost plus exile three other cards from your graveyard. (You may cast cards from your graveyard for their escape cost.)
At the beginning of the end step, sacrifice Underworld Breach.

March of Reckless Joy

As an additional cost to cast this spell, you may exile any number of red cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Exile the top X cards of your library. You may play up to two of those cards until the end of your next turn.

Siege-Gang Commander

When Siege-Gang Commander enters, create three 1/1 red Goblin creature tokens.
{1}{R}, Sacrifice a Goblin: Siege-Gang Commander deals 2 damage to any target.

Krenko, Mob Boss

{T}: Create X 1/1 red Goblin creature tokens, where X is the number of Goblins you control.

Sudden Breakthrough

Target creature gets +2/+0 and gains first strike until end of turn.
Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Brute Force

Target creature gets +3/+3 until end of turn.

Mind Stone

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

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Storm-Kiln Artist

Storm-Kiln Artist gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token.

Sol Ring

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Heat Shimmer

Create a token that's a copy of target creature, except it has haste and "At the beginning of the end step, exile this permanent."

Unleash Fury

Double the power of target creature until end of turn.

Chaotic Strike

Cast this spell only during combat after blockers are declared.
Flip a coin. If you win the flip, target creature gets +1/+1 until end of turn.
Draw a card.

Goblin Matron

When Goblin Matron enters, you may search your library for a Goblin card, reveal that card, put it into your hand, then shuffle.

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.)

Twinflame

Strive — This spell costs {2}{R} more to cast for each target beyond the first.
Choose any number of target creatures you control. For each of them, create a token that's a copy of that creature, except it has haste. Exile those tokens at the beginning of the next end step.

Panic

Cast this spell only during combat before blockers are declared.
Target creature can't block this turn.
Draw a card at the beginning of the next turn's upkeep.

Fists of Flame

Draw a card. Until end of turn, target creature gains trample and gets +1/+0 for each card you've drawn this turn. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)

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.

Strionic Resonator

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

Iron Myr

Dragon Fodder

Plague Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{T}: Add {C}.

Goblin Instigator

When Goblin Instigator enters, create a 1/1 red Goblin creature token.

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

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.")

Dualcaster Mage

Flash
When Dualcaster Mage enters, copy target instant or sorcery spell. You may choose new targets for the copy.

Otherworldly Outburst

Target creature gets +1/+0 until end of turn. When that creature dies this turn, create a 3/2 colorless Eldrazi Horror creature token.

Battle Hymn

Treasonous Ogre

Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Pay 3 life: Add {R}.

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

Reliquary Tower

Brute Strength

Target creature gets +3/+1 and gains trample until end of turn. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Reckless Charge

Target creature gets +3/+0 and gains haste until end of turn.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)