Dragon Tempest

Whenever a creature you control with flying enters, it gains haste until end of turn.
Whenever a Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.

Harness by Force

Strive — This spell costs {2}{R} more to cast for each target beyond the first.
Gain control of any number of target creatures until end of turn. Untap those creatures. They gain haste until end of turn.

Hijack

Gain control of target artifact or creature until end of turn. Untap it. It gains haste until end of turn.

Price of Progress

Price of Progress deals damage to each player equal to twice the number of nonbasic lands that player controls.

Scourge of Valkas

Flying
Whenever Scourge of Valkas or another Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.
{R}: Scourge of Valkas gets +1/+0 until end of 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.

Stormbreath Dragon

Flying, haste, protection from white
{5}{R}{R}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
When Stormbreath Dragon becomes monstrous, it deals damage to each opponent equal to the number of cards in that player's hand.

Zo-Zu the Punisher

Whenever a land enters, Zo-Zu the Punisher deals 2 damage to that land's controller.

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

Greater Gargadon

Suspend 10—{R}
Sacrifice an artifact, creature, or land: Remove a time counter from Greater Gargadon. Activate only if Greater Gargadon is suspended.

Flamebreak

Flamebreak deals 3 damage to each creature without flying and each player. Creatures dealt damage this way can't be regenerated this turn.

Barrage of Expendables

{R}, Sacrifice a creature: Barrage of Expendables deals 1 damage to any target.

Turn Against

Devoid (This card has no color.)
Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.

Terror of the Peaks

Flying
Spells your opponents cast that target Terror of the Peaks cost an additional 3 life to cast.
Whenever another creature you control enters, Terror of the Peaks deals damage equal to that creature's power to any target.

Grab the Reins

Choose one —
• Until end of turn, you gain control of target creature and it gains haste.
• Sacrifice a creature. Grab the Reins deals damage equal to that creature's power to any target.
Entwine {2}{R} (Choose both if you pay the entwine cost.)

Volcanic Offering

Destroy target nonbasic land you don't control and target nonbasic land of an opponent's choice you don't control.
Volcanic Offering deals 7 damage to target creature you don't control and 7 damage to target creature of an opponent's choice you don't control.

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.

Sin Prodder

Menace
At the beginning of your upkeep, reveal the top card of your library. Any opponent may have you put that card into your graveyard. If a player does, Sin Prodder deals damage to that player equal to that card's mana value. Otherwise, put that card into your hand.

Valakut, the Molten Pinnacle

Valakut, the Molten Pinnacle enters tapped.
Whenever a Mountain you control enters, if you control at least five other Mountains, you may have Valakut, the Molten Pinnacle deal 3 damage to any target.
{T}: Add {R}.

Abrade

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

Kari Zev, Skyship Raider

First strike, menace
Whenever Kari Zev, Skyship Raider attacks, create Ragavan, a legendary 2/1 red Monkey creature token. Ragavan enters tapped and attacking. Exile that token at end of combat.

Red Elemental Blast

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

Besmirch

Until end of turn, gain control of target creature and it gains haste. Untap and goad that creature. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Glorybringer

Flying, haste
You may exert Glorybringer as it attacks. When you do, it deals 4 damage to target non-Dragon creature an opponent controls. (An exerted creature won't untap during your next untap step.)

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Vicious Shadows

Whenever a creature dies, you may have Vicious Shadows deal damage to target player equal to the number of cards in that player's hand.

Sulfuric Vortex

At the beginning of each player's upkeep, Sulfuric Vortex deals 2 damage to that player.
If a player would gain life, that player gains no life instead.

Mass Mutiny

For each opponent, gain control of up to one target creature that player controls until end of turn. Untap those creatures. They gain haste until end of turn.

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Harsh Mentor

Whenever an opponent activates an ability of an artifact, creature, or land on the battlefield, if it isn't a mana ability, Harsh Mentor deals 2 damage to that player.

Arcane Signet

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

Sarkhan the Masterless

Whenever a creature attacks you or a planeswalker you control, each Dragon you control deals 1 damage to that creature.
+1: Until end of turn, each planeswalker you control becomes a 4/4 red Dragon creature and gains flying.
−3: Create a 4/4 red Dragon creature token with flying.

Hellrider

Haste
Whenever a creature you control attacks, Hellrider deals 1 damage to the player or planeswalker it's attacking.

Pyroblast

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

Rampaging Ferocidon

Menace
Players can't gain life.
Whenever another creature enters, Rampaging Ferocidon deals 1 damage to that creature's controller.

Fire Diamond

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

Zealous Conscripts

Haste
When Zealous Conscripts enters, gain control of target permanent until end of turn. Untap that permanent. It gains haste until end of turn.

Scourge of the Throne

Flying
Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Whenever Scourge of the Throne attacks for the first time each turn, if it's attacking the player with the most life or tied for most life, untap all attacking creatures. After this phase, there is an additional combat phase.

Mana Geyser

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

Drakuseth, Maw of Flames

Flying
Whenever Drakuseth attacks, it deals 4 damage to any target and 3 damage to each of up to two other targets.

Irencrag Feat

Add seven {R}. You can cast only one more spell this turn.

Sundering Stroke

Sundering Stroke deals 7 damage divided as you choose among one, two, or three targets. If at least seven red mana was spent to cast this spell, instead Sundering Stroke deals 7 damage to each of those permanents and/or players.

Molten Primordial

Haste
When Molten Primordial enters, for each opponent, gain control of up to one target creature that player controls until end of turn. Untap those creatures. They gain haste until end of turn.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Thundermaw Hellkite

Flying
Haste (This creature can attack and {T} as soon as it comes under your control.)
When Thundermaw Hellkite enters, it deals 1 damage to each creature with flying your opponents control. Tap those creatures.

Jeska, Thrice Reborn

Jeska, Thrice Reborn enters with a loyalty counter on her for each time you've cast a commander from the command zone this game.
0: Choose target creature. Until your next turn, if that creature would deal combat damage to one of your opponents, it deals triple that damage to that player instead.
−X: Jeska, Thrice Reborn deals X damage to each of up to three targets.
Jeska, Thrice Reborn can be your commander.
Partner

Citadel of Pain

At the beginning of each player's end step, Citadel of Pain deals X damage to that player, where X is the number of untapped lands they control.

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.

Hanweir Garrison

Whenever Hanweir Garrison attacks, create two 1/1 red Human creature tokens that are tapped and attacking.
(Melds with Hanweir Battlements.)

Sol Ring

Blasphemous Act

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

Ruby Medallion

Red spells you cast cost {1} less to cast.

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.

Territorial Hellkite

Flying, haste
At the beginning of combat on your turn, choose an opponent at random that Territorial Hellkite didn't attack during your last combat. Territorial Hellkite attacks that player this combat if able. If you can't choose an opponent this way, tap Territorial Hellkite.

Word of Seizing

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Untap target permanent and gain control of it until end of turn. It gains haste until end of turn.

Seething Song

Goblin Chainwhirler

First strike
When Goblin Chainwhirler enters, it deals 1 damage to each opponent and each creature and planeswalker they control.

Traitorous Blood

Gain control of target creature until end of turn. Untap it. It gains trample and haste until end of turn.

Jeska's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Add {R} for each card in target opponent's hand.
• Exile the top three cards of your library. You may play them this turn.

Act of Aggression

({R/P} can be paid with either {R} or 2 life.)
Gain control of target creature an opponent controls until end of turn. Untap that creature. It gains haste until end of turn.

Makeshift Munitions

{1}, Sacrifice an artifact or creature: Makeshift Munitions deals 1 damage to any target.

Pyrohemia

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pyrohemia.
{R}: Pyrohemia deals 1 damage to each creature and each player.

Leyline Tyrant

Flying
You don't lose unspent red mana as steps and phases end.
When Leyline Tyrant dies, you may pay any amount of {R}. When you do, it deals that much damage to any target.

Goblin Bombardment

Sacrifice a creature: Goblin Bombardment deals 1 damage to any target.

Mountain

Volcanic Fallout

This spell can't be countered.
Volcanic Fallout deals 2 damage to each creature and each player.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Shattering Spree

Replicate {R} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)
Destroy target artifact.

Spawning Pit

Sacrifice a creature: Put a charge counter on Spawning Pit.
{1}, Remove two charge counters from Spawning Pit: Create a 2/2 colorless Spawn artifact creature token.

High Market

{T}: Add {C}.
{T}, Sacrifice a creature: You gain 1 life.

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.")

Blazing Sunsteel

Equipped creature gets +1/+0 for each opponent you have.
Whenever equipped creature is dealt damage, it deals that much damage to any target.
Equip {4}

Guttersnipe

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

Hour of Devastation

All creatures lose indestructible until end of turn. Hour of Devastation deals 5 damage to each creature and each non-Bolas planeswalker.