Llanowar Elves

Hashep Oasis

{T}: Add {C}.
{T}, Pay 1 life: Add {G}.
{1}{G}{G}, {T}, Sacrifice a Desert: Target creature gets +3/+3 until end of turn. Activate only as a sorcery.

Experiment One

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Remove two +1/+1 counters from this creature: Regenerate it. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Yorvo, Lord of Garenbrig

Yorvo enters with four +1/+1 counters on it.
Whenever another green creature you control enters, put a +1/+1 counter on Yorvo. Then if that creature's power is greater than Yorvo's power, put another +1/+1 counter on Yorvo.

Primal Might

Target creature you control gets +X/+X until end of turn. Then it fights up to one target creature you don't control. (Each deals damage equal to its power to the other.)

Thrashing Brontodon

{1}, Sacrifice this creature: Destroy target artifact or enchantment.

Stonecoil Serpent

Reach, trample, protection from multicolored
This creature enters with X +1/+1 counters on it.

Barkhide Troll

This creature enters with a +1/+1 counter on it.
{1}, Remove a +1/+1 counter from this creature: This creature gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

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.)

Getting

Colossal Rattlewurm

Colossal Rattlewurm has flash as long as you control a Desert.
Trample
{1}{G}, Exile this card from your graveyard: Search your library for a Desert card, put it onto the battlefield tapped, then shuffle.

Scavenging Ooze

{G}: Exile target card from a graveyard. If it was a creature card, put a +1/+1 counter on this creature and you gain 1 life.

Steel Leaf Champion

This creature can't be blocked by creatures with power 2 or less.

Ulvenwald Behemoth

Trample, haste
Other creatures you control get +1/+1 and have trample and haste.

Ulvenwald Oddity

Trample, haste
{5}{G}{G}: Transform this creature.

Ulvenwald Oddity // Ulvenwald Behemoth

Garruk's Harbinger

Hexproof from black
Whenever this creature deals combat damage to a player or planeswalker, look at that many cards from the top of your library. You may reveal a creature card or Garruk planeswalker card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Werewolf Pack Leader

Pack tactics — Whenever this creature attacks, if you attacked with creatures with total power 6 or greater this combat, draw a card.
{3}{G}: Until end of turn, this creature has base power and toughness 5/3, gains trample, and isn't a Human.

Pelt Collector

Whenever another creature you control enters or dies, if that creature's power is greater than this creature's, put a +1/+1 counter on this creature.
As long as this creature has three or more +1/+1 counters on it, it has trample.

Chainweb Aracnir

Reach
When this creature enters, it deals damage equal to its power to target creature with flying an opponent controls.
Escape—{3}{G}{G}, Exile four other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)
This creature escapes with three +1/+1 counters on it.

Modern

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When this Aura is put into a graveyard from the battlefield, return it to its owner's hand.

Forest

Ram Through

Target creature you control deals damage equal to its power to target creature you don't control. If the creature you control has trample, excess damage is dealt to that creature's controller instead.

The Hunter Maze

This land enters tapped.
{T}: Add {G}.
{1}{G}, {T}, Sacrifice this land: Draw a card.

Old-Growth Troll

Trample
When Old-Growth Troll dies, if it was a creature, return it to the battlefield. It's an Aura enchantment with enchant Forest you control and "Enchanted Forest has '{T}: Add {G}{G}' and '{1}, {T}, Sacrifice this land: Create a tapped 4/4 green Troll Warrior creature token with trample.'"

Lair of the Hydra

If you control two or more other lands, this land enters tapped.
{T}: Add {G}.
{X}{G}: Until end of turn, this land becomes an X/X green Hydra creature. It's still a land. X can't be 0.

Strangleroot Geist

Haste
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.)

Elvish Mystic

Shifting Ceratops

This spell can't be countered.
Protection from blue (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything blue.)
{G}: This creature gains your choice of reach, trample, or haste until end of turn.