Rolling Earthquake

Rolling Earthquake deals X damage to each creature without horsemanship and each player.

Truefire Captain

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Truefire Captain is dealt damage, it deals that much damage to target player.

Boros Reckoner

Whenever Boros Reckoner is dealt damage, it deals that much damage to any target.
{R/W}: Boros Reckoner gains first strike until end of turn.

Spitemare

Whenever Spitemare is dealt damage, it deals that much damage to any target.

Earthquake

Earthquake deals X damage to each creature without flying and each player.

Wrathful Red Dragon

Flying
Whenever a Dragon you control is dealt damage, it deals that much damage to any target that isn't a Dragon.

Brash Taunter

Indestructible
Whenever Brash Taunter is dealt damage, it deals that much damage to target opponent.
{2}{R}, {T}: Brash Taunter fights another target creature.

Howlpack Avenger

Whenever a permanent you control is dealt damage, Howlpack Avenger deals that much damage to any target.
{1}{R}: Howlpack Avenger gets +2/+0 until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Ill-Tempered Loner

Whenever Ill-Tempered Loner is dealt damage, it deals that much damage to any target.
{1}{R}: Ill-Tempered Loner gets +2/+0 until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Ill-Tempered Loner // Howlpack Avenger

Deafening Clarion

Choose one or both —
• Deafening Clarion deals 3 damage to each creature.
• Creatures you control gain lifelink until end of turn.

Burn Down the House

Choose one —
• Burn Down the House deals 5 damage to each creature and each planeswalker.
• Create three 1/1 red Devil creature tokens with "When this creature dies, it deals 1 damage to any target." They gain haste until end of turn.

Spiteful Banditry

When Spiteful Banditry enters, it deals X damage to each creature.
Whenever one or more creatures your opponents control die, you create a Treasure token. This ability triggers only once each turn.

Blasphemous Act

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

Spiteful Sliver

Sliver creatures you control have "Whenever this creature is dealt damage, it deals that much damage to target player or planeswalker."

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}

Sweltering Suns

Sweltering Suns deals 3 damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

Storm's Wrath

Storm's Wrath deals 4 damage to each creature and each planeswalker.

Mogg Maniac

Whenever Mogg Maniac is dealt damage, it deals that much damage to target opponent or planeswalker.