Firewild Borderpost

You may pay {1} and return a basic land you control to its owner's hand rather than pay this spell's mana cost.
Firewild Borderpost 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 Emissary

When Burning-Tree Emissary enters, add {R}{G}.

Evolving Wilds

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

Mudbrawler Cohort

Haste
Mudbrawler Cohort gets +1/+1 as long as you control another red creature.

Wild Cantor

({R/G} can be paid with either {R} or {G}.)
Sacrifice Wild Cantor: Add one mana of any color.

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

Forest

Frenzied Goblin

Whenever this creature attacks, you may pay {R}. If you do, target creature can't block this turn.

Colossal Dreadmaw

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Rip-Clan Crasher

Jund Hackblade

As long as you control another multicolored permanent, Jund Hackblade gets +1/+1 and has haste.

Elephant Guide

Enchant creature
Enchanted creature gets +3/+3.
When enchanted creature dies, create a 3/3 green Elephant creature token.

Mountain

Naya Hushblade

As long as you control another multicolored permanent, Naya Hushblade gets +1/+1 and has shroud. (It can't be the target of spells or abilities.)