Kird Ape

Kird Ape gets +1/+2 as long as you control a Forest.

Pyroclasm

Pyroclasm deals 2 damage to each creature.

Karplusan Forest

{T}: Add {C}.
{T}: Add {R} or {G}. Karplusan Forest deals 1 damage to you.

Giant Trap Door Spider

{1}{R}{G}, {T}: Exile Giant Trap Door Spider and target creature without flying that's attacking you.

Fyndhorn Elves

Fork

Copy target instant or sorcery spell, except that the copy is red. You may choose new targets for the copy.

Mountain

Ball Lightning

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice Ball Lightning.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Tinder Wall

Defender (This creature can't attack.)
Sacrifice Tinder Wall: Add {R}{R}.
{R}, Sacrifice Tinder Wall: It deals 2 damage to target creature it's blocking.

Fire Sprites

Blood Lust

If target creature has toughness 5 or greater, it gets +4/-4 until end of turn. Otherwise, it gets +4/-X until end of turn, where X is its toughness minus 1.

Battle Frenzy

Green creatures you control get +1/+1 until end of turn.
Nongreen creatures you control get +1/+0 until end of turn.

Giant Growth

Target creature gets +3/+3 until end of turn.

Forest

Flashfires

Orcish Lumberjack

{T}, Sacrifice a Forest: Add three mana in any combination of {R} and/or {G}.

Pendelhaven

{T}: Add {G}.
{T}: Target 1/1 creature gets +1/+2 until end of turn.

Tsunami

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.