Primal Bellow

Target creature gets +1/+1 until end of turn for each Forest you control.

Unnatural Predation

Target creature gets +1/+1 and gains trample until end of turn.

Llanowar Augur

Sacrifice this creature: Target creature gets +3/+3 and gains trample until end of turn. Activate only during your upkeep.

Mortal's Resolve

Target creature gets +1/+1 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Massive Might

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

Inner Calm, Outer Strength

Target creature gets +X/+X until end of turn, where X is the number of cards in your hand.

Ashnod's Intervention

Until end of turn, target creature gets +2/+0 and gains "When this creature dies or is put into exile from the battlefield, return it to its owner's hand."

Titanic Growth

Target creature gets +4/+4 until end of turn.

Unnatural Endurance

Devoid (This card has no color.)
Target creature gets +2/+0 until end of turn. Regenerate it.

Narcissism

{G}, Discard a card: Target creature gets +2/+2 until end of turn.
{G}, Sacrifice this enchantment: Target creature gets +2/+2 until end of turn.

Armor of Shadows

Until end of turn, target creature gets +1/+0 and gains indestructible. (Damage and effects that say "destroy" don't destroy it.)

Invigorate

If you control a Forest, rather than pay this spell's mana cost, you may have an opponent gain 3 life.
Target creature gets +4/+4 until end of turn.

Tainted Strike

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Bull's Strength

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

Predator's Strike

Target creature gets +3/+3 and gains trample until end of turn. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Unchecked Growth

Target creature gets +4/+4 until end of turn. If it's a Spirit, it gains trample until end of turn.

Prey's Vengeance

Target creature gets +2/+2 until end of turn.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Giant Growth

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

Strength of Cedars

Target creature gets +X/+X until end of turn, where X is the number of lands you control.

Fully Grown

Target creature gets +3/+3 until end of turn. Put a trample counter on it.

Might of Oaks

Target creature gets +7/+7 until end of turn.

Yargle and Multani

Big Play

Target creature gets +2/+2 and gains reach until end of turn. Put a +1/+1 counter on it. (A creature with reach can block creatures with flying.)

Crash the Ramparts

Target creature gets +3/+3 and gains trample until end of turn.

Groundswell

Target creature gets +2/+2 until end of turn.
Landfall — If you had a land enter the battlefield under your control this turn, that creature gets +4/+4 until end of turn instead.

Nantuko Mentor

{2}{G}, {T}: Target creature gets +X/+X until end of turn, where X is that creature's power.

Abnormal Endurance

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Unlikely Aid

Target creature gets +2/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Briarhorn

Flash
When this creature enters, target creature gets +3/+3 until end of turn.
Evoke {1}{G} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Boon of Boseiju

Target creature gets +X/+X until end of turn, where X is the greatest mana value among permanents you control. Untap it.

Power Matrix

{T}: Target creature gets +1/+1 and gains flying, first strike, and trample until end of turn.

Might of Old Krosa

Target creature gets +2/+2 until end of turn. If you cast this spell during your main phase, that creature gets +4/+4 until end of turn instead.

Alchemist's Gift

Target creature gets +1/+1 and gains your choice of deathtouch or lifelink until end of turn. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it. Damage dealt by a creature with lifelink also causes its controller to gain that much life.)