Burning-Tree Emissary

When Burning-Tree Emissary enters, add {R}{G}.

Rakdos Cackler

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.)

Foundry Street Denizen

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

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.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Mountain

Firefist Striker

Battalion — Whenever Firefist Striker and at least two other creatures attack, target creature can't block this turn.

Goblin Rabblemaster

Other Goblin creatures you control attack each combat if able.
At the beginning of combat on your turn, create a 1/1 red Goblin creature token with haste.
Whenever Goblin Rabblemaster attacks, it gets +1/+0 until end of turn for each other attacking Goblin.

Ash Zealot

First strike, haste
Whenever a player casts a spell from a graveyard, Ash Zealot deals 3 damage to that player.

Rubblebelt Maaka

Bloodrush — {R}, Discard Rubblebelt Maaka: Target attacking creature gets +3/+3 until end of turn.

Stoke the Flames

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Stoke the Flames deals 4 damage to any target.

Mutavault

{T}: Add {C}.
{1}: Mutavault becomes a 2/2 creature with all creature types until end of turn. It's still a land.