Grist, the Hunger Tide

As long as Grist isn't on the battlefield, it's a 1/1 Insect creature in addition to its other types.
+1: Create a 1/1 black and green Insect creature token, then mill a card. If an Insect card was milled this way, put a loyalty counter on Grist and repeat this process.
−2: You may sacrifice a creature. When you do, destroy target creature or planeswalker.
−5: Each opponent loses life equal to the number of creature cards in your graveyard.

Geralf's Messenger

This creature enters tapped.
When this creature enters, target opponent loses 2 life.
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.)

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.)

Reclamation Sage

When this creature enters, you may destroy target artifact or enchantment.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Khalni Garden

This land enters tapped.
When this land enters, create a 0/1 green Plant creature token.
{T}: Add {G}.

Nurturing Peatland

{T}, Pay 1 life: Add {B} or {G}.
{1}, {T}, Sacrifice this land: Draw a card.

Essence Warden

Whenever another creature enters, you gain 1 life.

Eldritch Evolution

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a creature card with mana value X or less, where X is 2 plus the sacrificed creature's mana value. Put that card onto the battlefield, then shuffle. Exile Eldritch Evolution.

Swamp

Twilight Mire

{T}: Add {C}.
{B/G}, {T}: Add {B}{B}, {B}{G}, or {G}{G}.

Verdant Catacombs

{T}, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

Overgrown Tomb

({T}: Add {B} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Forest

Chord of Calling

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.

Wall of Roots

Defender
Put a -0/-1 counter on this creature: Add {G}. Activate only once each turn.

Birds of Paradise

Zulaport Cutthroat

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

Young Wolf

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.)

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.)

Blooming Marsh

This land enters tapped unless you control two or fewer other lands.
{T}: Add {B} or {G}.

Hapatra, Vizier of Poisons

Whenever Hapatra 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.

Dryad Arbor

(This land isn't a spell, it's affected by summoning sickness, and it has "{T}: Add {G}.")

Gilded Goose

Flying
When this creature enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
{1}{G}, {T}: Create a Food token.
{T}, Sacrifice a Food: Add one mana of any color.

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Ignoble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {B}, {R}, or {G}.