Goblin Arsonist

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

Manic Vandal

When Manic Vandal enters, destroy target artifact.

Lightning Mauler

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 Lightning Mauler is paired with another creature, both creatures have haste.

Seismic Strike

Seismic Strike deals damage to target creature equal to the number of Mountains you control.

Gore-House Chainwalker

Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

Violent Impact

Destroy target artifact or land.
Cycling {2} ({2}, Discard this card: Draw a card.)

Furor of the Bitten

Enchant creature
Enchanted creature gets +2/+2 and attacks each combat if able.

Spearpoint Oread

Bestow {5}{R} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
First strike
Enchanted creature gets +2/+2 and has first strike.

Goblin Wardriver

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)

Mountain

Kuldotha Ringleader

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Kuldotha Ringleader attacks each combat if able.

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Uncanny Speed

Target creature gets +3/+0 and gains haste until end of turn.

Foundry Street Denizen

Whenever another red creature you control enters, Foundry Street Denizen gets +1/+0 until end of turn.

Deathbellow Raider

Deathbellow Raider attacks each combat if able.
{2}{B}: Regenerate Deathbellow Raider.

Dragon Hatchling

Flying
{R}: Dragon Hatchling gets +1/+0 until end of turn.

Thatcher Revolt

Create three 1/1 red Human creature tokens with haste. Sacrifice those tokens at the beginning of the next end step.

Traitorous Blood

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

Zealous Conscripts

Haste
When Zealous Conscripts enters, gain control of target permanent until end of turn. Untap that permanent. It gains haste until end of turn.

Vulshok Heartstoker

When Vulshok Heartstoker enters, target creature gets +2/+0 until end of turn.

Goblin Balloon Brigade

{R}: Goblin Balloon Brigade gains flying until end of turn.

Arc Runner

Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice Arc Runner.

Ill-Tempered Cyclops

Trample
{5}{R}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

Ogre Resister

Fire Elemental

Chandra's Fury

Chandra's Fury deals 4 damage to target player or planeswalker and 1 damage to each creature that player or that planeswalker's controller controls.

Hellkite Charger

Flying, haste
Whenever Hellkite Charger attacks, you may pay {5}{R}{R}. If you do, untap all attacking creatures and after this phase, there is an additional combat phase.

Akoum Battlesinger

Haste
Whenever Akoum Battlesinger or another Ally you control enters, you may have Ally creatures you control get +1/+0 until end of turn.

Fiery Hellhound

{R}: Fiery Hellhound gets +1/+0 until end of turn.

Vulshok Berserker

Haste (This creature can attack and {T} as soon as it comes under your control.)

Splatter Thug

First strike
Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)