Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

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.)

Pest Summoning

Create two 1/1 black and green Pest creature tokens with "When this creature dies, you gain 1 life."

Lair of the Hydra

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

Snow-Covered Forest

Wrenn and Seven

+1: Reveal the top four cards of your library. Put all land cards revealed this way into your hand and the rest into your graveyard.
0: Put any number of land cards from your hand onto the battlefield tapped.
−3: Create a green Treefolk creature token with reach and "This creature's power and toughness are each equal to the number of lands you control."
−8: Return all permanent cards from your graveyard to your hand. You get an emblem with "You have no maximum hand size."

Jaspera Sentinel

Reach
{T}, Tap an untapped creature you control: Add one mana of any color.

Gnarled Professor

Trample
When Gnarled Professor enters the battlefield, learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Containment Breach

Destroy target artifact or enchantment. If its mana value is 2 or less, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."

Mascot Exhibition

Create a 2/1 white and black Inkling creature token with flying, a 3/2 red and white Spirit creature token, and a 4/4 blue and red Elemental creature token.

Lotus Cobra

Landfall — Whenever a land enters the battlefield under your control, add one mana of any color.

Sculptor of Winter

Esika's Chariot

When Esika's Chariot enters the battlefield, create two 2/2 green Cat creature tokens.
Whenever Esika's Chariot attacks, create a token that's a copy of target token you control.
Crew 4

Blizzard Brawl

Choose target creature you control and target creature you don't control. If you control three or more snow permanents, the creature you control gets +1/+0 and gains indestructible until end of turn. Then those creatures fight each other. (Each deals damage equal to its power to the other.)

Werewolf Pack Leader

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

Ranger Class

(Gain the next level as a sorcery to add its ability.)
When Ranger Class enters the battlefield, create a 2/2 green Wolf creature token.
{1}{G}: Level 2
Whenever you attack, put a +1/+1 counter on target attacking creature.
{3}{G}: Level 3
You may look at the top card of your library any time.
You may cast creature spells from the top of your library.

Expanded Anatomy

Put two +1/+1 counters on target creature. It gains vigilance until end of turn.

Environmental Sciences

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. You gain 2 life.

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.'"

Faceless Haven

{T}: Add {C}.
{S}{S}{S}: Faceless Haven becomes a 4/3 creature with vigilance and all creature types until end of turn. It's still a land. ({S} can be paid with one mana from a snow source.)

Primal Adversary

Trample
When Primal Adversary enters the battlefield, you may pay {1}{G} any number of times. When you pay this cost one or more times, put that many +1/+1 counters on Primal Adversary, then up to that many target lands you control become 3/3 Wolf creatures with haste that are still lands.