Hissing Quagmire

This land enters tapped.
{T}: Add {B} or {G}.
{1}{B}{G}: This land becomes a 2/2 black and green Elemental creature with deathtouch until end of turn. It's still a land.

Life from the Loam

Return up to three target land cards from your graveyard to your hand.
Dredge 3 (If you would draw a card, you may mill three cards instead. If you do, return this card from your graveyard to your hand.)

Wasteland

{T}: Add {C}.
{T}, Sacrifice this land: Destroy target nonbasic land.

Ramunap Excavator

Crucible of Worlds

Den of the Bugbear

If you control two or more other lands, this land enters tapped.
{T}: Add {R}.
{3}{R}: Until end of turn, this land becomes a 3/2 red Goblin creature with "Whenever this creature attacks, create a 1/1 red Goblin creature token that's tapped and attacking." It's still a land.

Devastating Summons

As an additional cost to cast this spell, sacrifice X lands.
Create two X/X red Elemental creature tokens.

Curse of the Restless Dead

Enchant player
Whenever a land enchanted player controls enters, you create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Nantuko Monastery

{T}: Add {C}.
Threshold — {G}{W}: This land becomes a 4/4 green and white Insect Monk creature with first strike until end of turn. It's still a land. Activate only if seven or more cards are in your graveyard.

Custody Battle

Enchant creature
Enchanted creature has "At the beginning of your upkeep, target opponent gains control of this creature unless you sacrifice a land."

Crop Rotation

As an additional cost to cast this spell, sacrifice a land.
Search your library for a land card, put that card onto the battlefield, then shuffle.

Raging Ravine

This land enters tapped.
{T}: Add {R} or {G}.
{2}{R}{G}: Until end of turn, this land becomes a 3/3 red and green Elemental creature with "Whenever this creature attacks, put a +1/+1 counter on it." It's still a land.