Life and Limb

All Forests and all Saprolings are 1/1 green Saproling creatures and Forest lands in addition to their other types. (They're affected by summoning sickness.)

Devoted Druid

{T}: Add {G}.
Put a -1/-1 counter on Devoted Druid: Untap Devoted Druid.

Bastion of Remembrance

When Bastion of Remembrance enters the battlefield, create a 1/1 white Human Soldier creature token.
Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

Jade Mage

{2}{G}: Create a 1/1 green Saproling creature token.

Pitiless Plunderer

Whenever another creature you control dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Yawgmoth, Thran Physician

Protection from Humans
Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card.
{B}{B}, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Ruthless Knave

{2}{B}, Sacrifice a creature: Create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")
Sacrifice three Treasures: Draw a card.

Scurry Oak

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on Scurry Oak, you may create a 1/1 green Squirrel creature token.

Chatterfang, Squirrel General

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
If one or more tokens would be created under your control, those tokens plus that many 1/1 green Squirrel creature tokens are created instead.
{B}, Sacrifice X Squirrels: Target creature gets +X/-X until end of turn.

Parallel Lives

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Hapatra, Vizier of Poisons

Whenever Hapatra, Vizier of Poisons deals combat damage to a player, you may put a -1/-1 counter on target creature.
Whenever you put one or more -1/-1 counters on a creature, create a 1/1 green Snake creature token with deathtouch.

Necrotic Ooze

As long as Necrotic Ooze is on the battlefield, it has all activated abilities of all creature cards in all graveyards.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Ivy Lane Denizen

Whenever another green creature enters the battlefield under your control, put a +1/+1 counter on target creature.

Ashnod's Altar

Moldervine Reclamation

Whenever a creature you control dies, you gain 1 life and draw a card.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Trudge Garden

Whenever you gain life, you may pay {2}. If you do, create a 4/4 green Fungus Beast creature token with trample.

Channeler Initiate

When Channeler Initiate enters the battlefield, put three -1/-1 counters on target creature you control.
{T}, Remove a -1/-1 counter from Channeler Initiate: Add one mana of any color.

Evolution Sage

Landfall — Whenever a land enters the battlefield under your control, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Savra, Queen of the Golgari

Whenever you sacrifice a black creature, you may pay 2 life. If you do, each other player sacrifices a creature.
Whenever you sacrifice a green creature, you may gain 2 life.