Hellfire Mongrel

At the beginning of each opponent's upkeep, if that player has two or fewer cards in hand, this creature deals 2 damage to that player.

Spark Elemental

Trample, haste (This creature can deal excess combat damage to the player or planeswalker it's attacking. This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.

Lightning Elemental

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

Ball Lightning

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.

Earth Elemental

Akoum Stonewaker

Landfall — Whenever a land you control enters, you may pay {2}{R}. If you do, create a 3/1 red Elemental creature token with trample and haste. Exile that token at the beginning of the next end step.

Cinder Pyromancer

{T}: This creature deals 1 damage to target player or planeswalker.
Whenever you cast a red spell, you may untap this creature.

Cinder Elemental

{X}{R}, {T}, Sacrifice this creature: It deals X damage to any target.

Heartlash Cinder

Haste
Chroma — When this creature enters, it gets +X/+0 until end of turn, where X is the number of red mana symbols in the mana costs of permanents you control.

Cosi's Ravager

Landfall — Whenever a land you control enters, you may have this creature deal 1 damage to target player or planeswalker.

Wall of Fire

Defender (This creature can't attack.)
{R}: This creature gets +1/+0 until end of turn.

Inferno Elemental

Whenever this creature blocks or becomes blocked by a creature, this creature deals 3 damage to that creature.

Molten Ravager

{R}: This creature gets +1/+0 until end of turn.

Fiery Hellhound

Kiln Fiend

Whenever you cast an instant or sorcery spell, this creature gets +3/+0 until end of turn.