Wild Nacatl

Wild Nacatl gets +1/+1 as long as you control a Mountain.
Wild Nacatl gets +1/+1 as long as you control a Plains.

Highland Forest

({T}: Add {R} or {G}.)
Highland Forest enters tapped.

Horned Kavu

When Horned Kavu enters, return a red or green creature you control to its owner's hand.

Young Wolf

Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Skred

Skred deals damage to target creature equal to the number of snow permanents you control.

Snow-Covered Forest

Crimson Fleet Commodore

Trample
When Crimson Fleet Commodore enters, you become the monarch.

Kor Skyfisher

Flying
When Kor Skyfisher enters, return a permanent you control to its owner's hand.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Alpine Meadow

({T}: Add {R} or {W}.)
Alpine Meadow enters tapped.

Snow-Covered Plains

Kird Ape

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

Goblin Bushwhacker

Kicker {R} (You may pay an additional {R} as you cast this spell.)
When Goblin Bushwhacker enters, if it was kicked, creatures you control get +1/+0 and gain haste until end of turn.

Burning-Tree Emissary

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

Keldon Marauders

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Keldon Marauders enters or leaves the battlefield, it deals 1 damage to target player or planeswalker.

Sarulf's Packmate

When Sarulf's Packmate enters, draw a card.
Foretell {1}{G} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)