Mountain

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on Forgotten Ancient.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Forgotten Ancient onto other creatures.

Gaea's Revenge

This spell can't be countered.
Haste
Gaea's Revenge can't be the target of nongreen spells or abilities from nongreen sources.

Silvos, Rogue Elemental

Trample
{G}: Regenerate Silvos, Rogue Elemental.

Akoum Hellhound

Landfall — Whenever a land enters the battlefield under your control, Akoum Hellhound gets +2/+2 until end of turn.

Magmasaur

Magmasaur enters the battlefield with five +1/+1 counters on it.
At the beginning of your upkeep, you may remove a +1/+1 counter from Magmasaur. If you don't, sacrifice Magmasaur and it deals damage equal to the number of +1/+1 counters on it to each creature without flying and each player.

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.

Brushfire Elemental

Haste
Brushfire Elemental can't be blocked by creatures with power 2 or less.
Landfall — Whenever a land enters the battlefield under your control, Brushfire Elemental gets +2/+2 until end of turn.

Leafkin Avenger

{T}: Add {G} for each creature with power 4 or greater you control.
{7}{R}: Leafkin Avenger deals damage equal to its power to target player or planeswalker.

Awakened Skyclave

Vigilance, haste
As long as Awakened Skyclave is on the battlefield, it's a land in addition to its other types.
{T}: Add one mana of any color.

Invasion of Zendikar

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Zendikar enters the battlefield, search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Invasion of Zendikar // Awakened Skyclave

Forest

Worldsoul's Rage

Worldsoul's Rage deals X damage to any target. Put up to X land cards from your hand and/or graveyard onto the battlefield tapped.

Brighthearth Banneret

Elemental spells and Warrior spells you cast cost {1} less to cast.
Reinforce 1—{1}{R} ({1}{R}, Discard this card: Put a +1/+1 counter on target creature.)

Omnath, Locus of Rage

Landfall — Whenever a land enters the battlefield under your control, create a 5/5 red and green Elemental creature token.
Whenever Omnath, Locus of Rage or another Elemental you control dies, Omnath deals 3 damage to any target.

Riveteers Overlook

When Riveteers Overlook enters the battlefield, sacrifice it. When you do, search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Seed Guardian

Reach
When Seed Guardian dies, create an X/X green Elemental creature token, where X is the number of creature cards in your graveyard.

Cosi's Ravager

Landfall — Whenever a land enters the battlefield under your control, you may have Cosi's Ravager deal 1 damage to target player or planeswalker.

Zendikar Incarnate

Zendikar Incarnate's power is equal to the number of lands you control.

Perennial Behemoth

You may play lands from your graveyard.
Unearth {G}{G} ({G}{G}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Smokebraider

{T}: Add two mana in any combination of colors. Spend this mana only to cast Elemental spells or activate abilities of Elementals.

Lavakin Brawler

Whenever Lavakin Brawler attacks, it gets +1/+0 until end of turn for each Elemental you control.

Creeperhulk

Trample
{1}{G}: Until end of turn, target creature you control has base power and toughness 5/5 and gains trample.

Living Twister

{1}{R}, Discard a land card: Living Twister deals 2 damage to any target.
{G}: Return a tapped land you control to its owner's hand.

Gaea's Gift

Put a +1/+1 counter on target creature you control. It gains reach, trample, hexproof, and indestructible until end of turn. (It can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Splinterfright

Trample
Splinterfright's power and toughness are each equal to the number of creature cards in your graveyard.
At the beginning of your upkeep, mill two cards.

Cabaretti Courtyard

When Cabaretti Courtyard enters the battlefield, sacrifice it. When you do, search your library for a basic Mountain, Forest, or Plains card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Incandescent Soulstoke

Other Elemental creatures you control get +1/+1.
{1}{R}, {T}: You may put an Elemental creature card from your hand onto the battlefield. That creature gains haste until end of turn. Sacrifice it at the beginning of the next end step.