Timber Gorge

This land enters tapped.
{T}: Add {R} or {G}.

Violent Outburst

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Creatures you control get +1/+0 until end of turn.

Burning-Tree Vandal

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Whenever this creature attacks, you may discard a card. If you do, draw a card.

Reckless Impulse

Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Shock

Clan Guildmage

{1}{R}, {T}: Target creature can't block this turn.
{2}{G}, {T}: Target land you control becomes a 4/4 Elemental creature with haste until end of turn. It's still a land.

Domri, Chaos Bringer

+1: Add {R} or {G}. If that mana is spent on a creature spell, it gains riot. (It enters with your choice of a +1/+1 counter or haste.)
−3: Look at the top four cards of your library. You may reveal up to two creature cards from among them and put them into your hand. Put the rest on the bottom of your library in a random order.
−8: You get an emblem with "At the beginning of each end step, create a 4/4 red and green Beast creature token with trample."

Break Out

Look at the top six cards of your library. You may reveal a creature card from among them. If that card has mana value 2 or less, you may put it onto the battlefield and it gains haste until end of turn. If you didn't put the revealed card onto the battlefield this way, put it into your hand. Put the rest on the bottom of your library in a random order.

Forest

Colossus

Target creature gets +4/+2 and gains trample until end of turn.

Collision

Collision deals 6 damage to target creature with flying.

Collision // Colossus

Gruul Spellbreaker

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Trample
During your turn, you and this creature have hexproof.

Charging War Boar

Haste (This creature can attack and {T} as soon as it comes under your control.)
As long as you control a Domri planeswalker, this creature gets +1/+1 and has trample. (It can deal excess damage to the player or planeswalker it's attacking.)

Mountain

Zhur-Taa Goblin

Riot (This creature enters with your choice of a +1/+1 counter or haste.)

Clamor Shaman

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Whenever this creature attacks, target creature an opponent controls can't block this turn.