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.

Spawn of Thraxes

Flying
When Spawn of Thraxes enters, it deals damage to any target equal to the number of Mountains you control.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Searing Spear

Searing Spear deals 3 damage to any target.

Browbeat

Any player may have Browbeat deal 5 damage to them. If no one does, target player draws three cards.

Chandra, the Firebrand

+1: Chandra, the Firebrand deals 1 damage to any target.
−2: When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
−6: Chandra, the Firebrand deals 6 damage to each of up to six targets.

Price of Glory

Whenever a player taps a land for mana, if it's not that player's turn, destroy that land.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Spite of Mogis

Spite of Mogis deals damage to target creature equal to the number of instant and sorcery cards in your graveyard. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Searing Blood

Searing Blood deals 2 damage to target creature. When that creature dies this turn, Searing Blood deals 3 damage to the creature's controller.

Volcanic Geyser

Volcanic Geyser deals X damage to any target.

Hellion Crucible

{T}: Add {C}.
{1}{R}, {T}: Put a pressure counter on Hellion Crucible.
{1}{R}, {T}, Remove two pressure counters from Hellion Crucible and sacrifice it: Create a 4/4 red Hellion creature token with haste. (It can attack and {T} as soon as it comes under your control.)

Firedrinker Satyr

Whenever Firedrinker Satyr is dealt damage, it deals that much damage to you.
{1}{R}: Firedrinker Satyr gets +1/+0 until end of turn and deals 1 damage to you.

Goblin Arsonist

When Goblin Arsonist dies, you may have it deal 1 damage to any target.

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Skullscorch

Target player discards two cards at random unless that player has Skullscorch deal 4 damage to them.

Magma Spray

Magma Spray deals 2 damage to target creature. If that creature would die this turn, exile it instead.

Grim Lavamancer

{R}, {T}, Exile two cards from your graveyard: Grim Lavamancer deals 2 damage to any target.

Mountain

Sigiled Skink

Whenever Sigiled Skink attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Magma Jet

Magma Jet deals 2 damage to any target. Scry 2.

Satyr Firedancer

Whenever an instant or sorcery spell you control deals damage to an opponent, Satyr Firedancer deals that much damage to target creature that player controls.

Lava Dart

Lava Dart deals 1 damage to any target.
Flashback—Sacrifice a Mountain. (You may cast this card from your graveyard for its flashback cost. Then exile it.)