Skyshroud Cutter

If you control a Forest, rather than pay this spell's mana cost, you may have each other player gain 5 life.

Mox Emerald

Allosaurus Rider

You may exile two green cards from your hand rather than pay this spell's mana cost.
Allosaurus Rider's power and toughness are each equal to 1 plus the number of lands you control.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Metamorphosis

As an additional cost to cast this spell, sacrifice a creature.
Add X mana of any one color, where X is 1 plus the sacrificed creature's mana value. Spend this mana only to cast creature spells.

Griselbrand

Flying, lifelink
Pay 7 life: Draw seven cards.

Vine Dryad

You may exile a green card from your hand rather than pay this spell's mana cost.
Flash
Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)

Forest

Food Chain

Exile a creature you control: Add X mana of any one color, where X is 1 plus the exiled creature's mana value. Spend this mana only to cast creature spells.

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Skithiryx, the Blight Dragon

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{B}: Skithiryx, the Blight Dragon gains haste until end of turn.
{B}{B}: Regenerate Skithiryx.