Overgrowth Elemental

When Overgrowth Elemental enters, put a +1/+1 counter on another target Elemental you control.
Whenever another creature you control dies, you gain 1 life. If that creature was an Elemental, put a +1/+1 counter on Overgrowth Elemental.

Scampering Scorcher

When Scampering Scorcher enters, create two 1/1 red Elemental creature tokens. Elementals you control gain haste until end of turn. (They can attack and {T} this turn.)

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Chandra, Novice Pyromancer

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

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Island

Temple of Mystery

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {G} or {U}.

Risen Reef

Whenever Risen Reef or another Elemental you control enters, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand.

Unsummon

Return target creature to its owner's hand.

Chandra's Spitfire

Flying
Whenever an opponent is dealt noncombat damage, Chandra's Spitfire gets +3/+0 until end of turn.

Negate

Temple of Epiphany

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {R}.

Thunderkin Awakener

Haste
Whenever Thunderkin Awakener attacks, choose target Elemental creature card in your graveyard with toughness less than Thunderkin Awakener's toughness. Return that card to the battlefield tapped and attacking. Sacrifice it at the beginning of the next end step.

Mountain

Seasonal Ritual

Add one mana of any color. (Then exile this card. You may cast the creature later from exile.)

Rosethorn Acolyte

Rosethorn Acolyte // Seasonal Ritual

Omnath, Locus of the Roil

When Omnath, Locus of the Roil enters, it deals damage to any target equal to the number of Elementals you control.
Landfall — Whenever a land you control enters, put a +1/+1 counter on target Elemental you control. If you control eight or more lands, draw a card.

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.

Anticipate

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Lightning Stormkin

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

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Creeping Trailblazer

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

Forest

Ferocity of the Wilds

Attacking non-Human creatures you control get +1/+0 and have trample.

Cloudkin Seer

Flying
When Cloudkin Seer enters, draw a card.

Stomping Ground

({T}: Add {R} or {G}.)
As Stomping Ground enters, you may pay 2 life. If you don't, it enters tapped.

Leafkin Druid

{T}: Add {G}. If you control four or more creatures, add {G}{G} instead.

Lava Coil

Lava Coil deals 4 damage to target creature. If that creature would die this turn, exile it instead.

Thicket Crasher

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Other Elementals you control have trample.