Voracious Hydra

Trample
Voracious Hydra enters with X +1/+1 counters on it.
When Voracious Hydra enters, choose one —
• Double the number of +1/+1 counters on Voracious Hydra.
• Voracious Hydra fights target creature you don't control.

Forest

Vivien, Arkbow Ranger

+1: Distribute two +1/+1 counters among up to two target creatures. They gain trample until end of turn.
−3: Target creature you control deals damage equal to its power to target creature or planeswalker.
−5: You may reveal a creature card you own from outside the game and put it into your hand.

Walking Ballista

Walking Ballista enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on Walking Ballista.
Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.

Nissa, Who Shakes the World

Whenever you tap a Forest for mana, add an additional {G}.
+1: Put three +1/+1 counters on up to one target noncreature land you control. Untap it. It becomes a 0/0 Elemental creature with vigilance and haste that's still a land.
−8: You get an emblem with "Lands you control have indestructible." Search your library for any number of Forest cards, put them onto the battlefield tapped, then shuffle.

Rishkar, Peema Renegade

When Rishkar, Peema Renegade enters, put a +1/+1 counter on each of up to two target creatures.
Each creature you control with a counter on it has "{T}: Add {G}."

Steel Leaf Champion

Steel Leaf Champion can't be blocked by creatures with power 2 or less.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Barkhide Troll

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

Questing Beast

Vigilance, deathtouch, haste
Questing Beast can't be blocked by creatures with power 2 or less.
Combat damage that would be dealt by creatures you control can't be prevented.
Whenever Questing Beast deals combat damage to an opponent, it deals that much damage to target planeswalker that player controls.

Elvish Mystic

Avatar of the Resolute

Reach, trample
Avatar of the Resolute enters with a +1/+1 counter on it for each other creature you control with a +1/+1 counter on it.

Nissa, Voice of Zendikar

+1: Create a 0/1 green Plant creature token.
−2: Put a +1/+1 counter on each creature you control.
−7: You gain X life and draw X cards, where X is the number of lands you control.

Stonecoil Serpent

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

Castle Garenbrig

Castle Garenbrig enters tapped unless you control a Forest.
{T}: Add {G}.
{2}{G}{G}, {T}: Add six {G}. Spend this mana only to cast creature spells or activate abilities of creatures.

Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Llanowar Elves

The Great Henge

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
{T}: Add {G}{G}. You gain 2 life.
Whenever a nontoken creature you control enters, put a +1/+1 counter on it and draw a card.