Dictate of the Twin Gods

Flash
If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Pandemonium

Whenever a creature enters, that creature's controller may have it deal damage equal to its power to any target of their choice.

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.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Moraug, Fury of Akoum

Each creature you control gets +1/+0 for each time it has attacked this turn.
Landfall — Whenever a land you control enters, if it's your main phase, there's an additional combat phase after this phase. At the beginning of that combat, untap all creatures you control.

Stolen Strategy

At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.

Pia Nalaar

When Pia Nalaar enters, create a 1/1 colorless Thopter artifact creature token with flying.
{1}{R}: Target artifact creature gets +1/+0 until end of turn.
{1}, Sacrifice an artifact: Target creature can't block this turn.

Illicit Auction

Each player may bid life for control of target creature. You start the bidding with a bid of 0. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid and gains control of the creature. (This effect lasts indefinitely.)

Guttersnipe

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

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Magus of the Moon

Blood Moon

Dong Zhou, the Tyrant

When Dong Zhou, the Tyrant enters, target creature an opponent controls deals damage equal to its power to that player.

Harmless Offering

Target opponent gains control of target permanent you control.

Furnace of Rath

If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Sol Ring

Abrade

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

Chandra, Flamecaller

+1: Create two 3/1 red Elemental creature tokens with haste. Exile them at the beginning of the next end step.
0: Discard all the cards in your hand, then draw that many cards plus one.
−X: Chandra, Flamecaller deals X damage to each creature.

Fire Diamond

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

Fanatic of Mogis

When Fanatic of Mogis enters, it deals damage to each opponent equal to your devotion to red. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)

Feldon of the Third Path

{2}{R}, {T}: Create a token that's a copy of target creature card in your graveyard, except it's an artifact in addition to its other types. It gains haste. Sacrifice it at the beginning of the next end step.

Gilded Lotus

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Ankh of Mishra

Whenever a land enters, Ankh of Mishra deals 2 damage to that land's controller.

Blasphemous Act

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

Thrill of Possibility

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

Tormenting Voice

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.)

Duplicant

Imprint — When Duplicant enters, you may exile target nontoken creature.
As long as a card exiled with Duplicant is a creature card, Duplicant has the power, toughness, and creature types of the last creature card exiled with Duplicant. It's still a Shapeshifter.

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Unwilling Recruit

Gain control of target creature until end of turn. Untap that creature. It gets +X/+0 and gains haste until end of turn.

Artifact Blast

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.)

Mirror March

Whenever a nontoken creature you control enters, flip a coin until you lose a flip. For each flip you won, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

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.")

Drakuseth, Maw of Flames

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

Crawlspace

No more than two creatures can attack you each combat.

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Brute Force

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

Umbilicus

At the beginning of each player's upkeep, that player may pay 2 life. If they don't, they return a permanent they control to its owner's hand.