Arbor Armament

Put a +1/+1 counter on target creature. That creature gains reach until end of turn. (It can block creatures with flying.)

Ent's Fury

Put a +1/+1 counter on target creature you control if its power is 4 or greater. Then that creature gets +1/+1 until end of turn and fights target creature you don't control.

Advocate of the Beast

At the beginning of your end step, put a +1/+1 counter on target Beast creature you control.

Hunger of the Howlpack

Put a +1/+1 counter on target creature.
Morbid — Put three +1/+1 counters on that creature instead if a creature died this turn.

Hunter's Edge

Put a +1/+1 counter on target creature you control. Then that creature deals damage equal to its power to target creature you don't control.

Ivy Lane Denizen

Whenever another green creature you control enters, put a +1/+1 counter on target creature.

Snakeskin Veil

Put a +1/+1 counter on target creature you control. It gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Herd Baloth

Whenever one or more +1/+1 counters are put on this creature, you may create a 4/4 green Beast creature token.

Outmuscle

Put a +1/+1 counter on target creature you control, then it fights target creature you don't control. (Each deals damage equal to its power to the other.)
Adamant — If at least three green mana was spent to cast this spell, the creature you control gains indestructible until end of turn.

Gaea's Gift

Put a +1/+1 counter on target creature you control. It gains reach, trample, hexproof, and indestructible until end of turn. (It can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Burst of Strength

Put a +1/+1 counter on target creature and untap it.

Snake Umbra

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals damage to an opponent, you may draw a card."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Fertilid's Favor

Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles. Put two +1/+1 counters on up to one target artifact or creature.

Scale the Heights

Put a +1/+1 counter on up to one target creature. You gain 2 life. You may play an additional land this turn.
Draw a card.

Placid Rottentail

Vigilance
{2}{G}, Exile this card from your graveyard: Put two +1/+1 counters on target creature. Activate only as a sorcery.