Cinder Elemental

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

Fiery Hellhound

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

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.

Kiln Fiend

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

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.

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.

Cinder Pyromancer

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

Molten Ravager

Cosi's Ravager

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

Lightning Elemental

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

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.

Earth Elemental

Inferno Elemental

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

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.

Wall of Fire

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