Champion of the Path

As an additional cost to cast this spell, behold an Elemental and exile it. (Exile an Elemental you control or an Elemental card from your hand.)
Whenever another Elemental you control enters, it deals damage equal to its power to each opponent.
When this creature leaves the battlefield, return the exiled card to its owner's hand.

Chandra, Flamecaller

+1: Create two 3/1 red Elemental creature tokens with haste. Exile them at the beginning of the next end step.
0: Discard all the cards in your hand, then draw that many cards plus one.
−X: Chandra deals X damage to each creature.

Devastating Summons

As an additional cost to cast this spell, sacrifice X lands.
Create two X/X red Elemental creature tokens.

Creeping Trailblazer

Other Elementals you control get +1/+0.
{2}{R}{G}: This creature gets +1/+1 until end of turn for each Elemental you control.

Deathleaper, Terror Weapon

Flash
Haste
Flesh Hooks — Creatures you control that entered this turn have double strike.

Chandra, Novice Pyromancer

+1: Elementals you control get +2/+0 until end of turn.
−1: Add {R}{R}.
−2: Chandra deals 2 damage to any target.

Chandra, Acolyte of Flame

0: Put a loyalty counter on each red planeswalker you control.
0: Create two 1/1 red Elemental creature tokens. They gain haste. Sacrifice them at the beginning of the next end step.
−2: You may cast target instant or sorcery card with mana value 3 or less from your graveyard. If that spell would be put into your graveyard, exile it instead.