Inferno Titan

{R}: Inferno Titan gets +1/+0 until end of turn.
Whenever Inferno Titan enters or attacks, it deals 3 damage divided as you choose among one, two, or three targets.

Volt Charge

Volt Charge deals 3 damage to any target. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Stromkirk Noble

Stromkirk Noble can't be blocked by Humans.
Whenever Stromkirk Noble deals combat damage to a player, put a +1/+1 counter on it.

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}.

Ratchet Bomb

{T}: Put a charge counter on Ratchet Bomb.
{T}, Sacrifice Ratchet Bomb: Destroy each nonland permanent with mana value equal to the number of charge counters on Ratchet Bomb.

Stormblood Berserker

Bloodthirst 2 (If an opponent was dealt damage this turn, this creature enters with two +1/+1 counters on it.)
Menace (This creature can't be blocked except by two or more creatures.)

Koth of the Hammer

+1: Untap target Mountain. It becomes a 4/4 red Elemental creature until end of turn. It's still a land.
−2: Add {R} for each Mountain you control.
−5: You get an emblem with "Mountains you control have '{T}: This land deals 1 damage to any target.'"

Mountain

Tibalt, the Fiend-Blooded

+1: Draw a card, then discard a card at random.
−4: Tibalt, the Fiend-Blooded deals damage equal to the number of cards in target player's hand to that player.
−6: Gain control of all creatures until end of turn. Untap them. They gain haste until end of turn.

Contagion Clasp

When Contagion Clasp enters, put a -1/-1 counter on target creature.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Shrine of Burning Rage

At the beginning of your upkeep and whenever you cast a red spell, put a charge counter on Shrine of Burning Rage.
{3}, {T}, Sacrifice Shrine of Burning Rage: It deals damage equal to the number of charge counters on it to any target.

Thunderous Wrath

Thunderous Wrath deals 5 damage to any target.
Miracle {R} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Rolling Temblor

Rolling Temblor deals 2 damage to each creature without flying.
Flashback {4}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Slagstorm

Choose one —
• Slagstorm deals 3 damage to each creature.
• Slagstorm deals 3 damage to each player.

Devil's Play

Devil's Play deals X damage to any target.
Flashback {X}{R}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Lux Cannon

{T}: Put a charge counter on Lux Cannon.
{T}, Remove three charge counters from Lux Cannon: Destroy target permanent.