Goblin Arsonist

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

Plated Geopede

First strike
Landfall — Whenever a land you control enters, Plated Geopede gets +2/+2 until end of turn.

Mountain

Traitorous Blood

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

Intimidator Initiate

Whenever a player casts a red spell, you may pay {1}. If you do, target creature can't block this turn.

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.'"

Vexing Devil

When Vexing Devil enters, any opponent may have it deal 4 damage to them. If a player does, sacrifice Vexing Devil.

Curse of Bloodletting

Enchant player
If a source would deal damage to enchanted player, it deals double that damage to that player instead.

Hound of Griselbrand

Double strike
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Somberwald Vigilante

Whenever Somberwald Vigilante becomes blocked by a creature, Somberwald Vigilante deals 1 damage to that creature.

Mogg Flunkies

Mogg Flunkies can't attack or block alone.

Ashmouth Hound

Whenever Ashmouth Hound blocks or becomes blocked by a creature, Ashmouth Hound deals 1 damage to that creature.

Fervent Cathar

Haste
When Fervent Cathar enters, target creature can't block this turn.

Archwing Dragon

Flying, haste
At the beginning of the end step, return Archwing Dragon to its owner's hand.

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Hellrider

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

Hanweir Lancer

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Hanweir Lancer is paired with another creature, both creatures have first strike.

Pyretic Ritual

Pitchburn Devils

When Pitchburn Devils dies, it deals 3 damage to any target.

Ironfang

First strike
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Ironfang.

Village Ironsmith

First strike
At the beginning of each upkeep, if no spells were cast last turn, transform Village Ironsmith.

Village Ironsmith // Ironfang

Blisterstick Shaman

When Blisterstick Shaman enters, it deals 1 damage to any target.

Ring of Valkas

Equipped creature has haste. (It can attack and {T} no matter when it came under your control.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's red.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Anger

Haste
As long as Anger is in your graveyard and you control a Mountain, creatures you control have haste.

Gang of Devils

When Gang of Devils dies, it deals 3 damage divided as you choose among one, two, or three targets.