Wastes

Warping Wail

({C} represents colorless mana.)
Choose one —
• Exile target creature with power or toughness 1 or less.
• Counter target sorcery spell.
• Create a 1/1 colorless Eldrazi Scion creature token. It has "Sacrifice this creature: Add {C}."

Swamp

Essence Depleter

Devoid (This card has no color.)
{1}{C}: Target opponent loses 1 life and you gain 1 life. ({C} represents colorless mana.)

Crumbling Vestige

Crumbling Vestige enters tapped.
When Crumbling Vestige enters, add one mana of any color.
{T}: Add {C}. ({C} represents colorless mana.)

Holdout Settlement

{T}: Add {C}. ({C} represents colorless mana.)
{T}, Tap an untapped creature you control: Add one mana of any color.

Hedron Crawler

{T}: Add {C}. ({C} represents colorless mana.)

Endbringer

Untap Endbringer during each other player's untap step.
{T}: Endbringer deals 1 damage to any target.
{C}, {T}: Target creature can't attack or block this turn.
{C}{C}, {T}: Draw a card.

Seer's Lantern

{T}: Add {C}.
{2}, {T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Dread Defiler

Devoid (This card has no color.)
{3}{C}, Exile a creature card from your graveyard: Target opponent loses life equal to the exiled card's power. ({C} represents colorless mana.)

Sifter of Skulls

Devoid (This card has no color.)
Whenever another nontoken creature you control dies, create a 1/1 colorless Eldrazi Scion creature token. It has "Sacrifice this creature: Add {C}." ({C} represents colorless mana.)

Sky Scourer

Devoid (This card has no color.)
Flying
Whenever you cast a colorless spell, Sky Scourer gets +1/+0 until end of turn.

Bearer of Silence

Devoid (This card has no color.)
When you cast this spell, you may pay {1}{C}. If you do, target opponent sacrifices a creature. ({C} represents colorless mana.)
Flying
Bearer of Silence can't block.

Slaughter Drone

Devoid (This card has no color.)
{C}: Slaughter Drone gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it. {C} represents colorless mana.)

Corpse Churn

Mill three cards, then you may return a creature card from your graveyard to your hand. (To mill three cards, put the top three cards of your library into your graveyard.)

Oblivion Strike

Devoid (This card has no color.)
Exile target creature.

Kozilek, the Great Distortion

When you cast this spell, if you have fewer than seven cards in hand, draw cards equal to the difference.
Menace
Discard a card with mana value X: Counter target spell with mana value X.

Thought-Knot Seer

({C} represents colorless mana.)
When Thought-Knot Seer enters, target opponent reveals their hand. You choose a nonland card from it and exile that card.
When Thought-Knot Seer leaves the battlefield, target opponent draws a card.

Stoneforge Masterwork

Equipped creature gets +1/+1 for each other creature you control that shares a creature type with it.
Equip {2}

Mirrorpool

Mirrorpool enters tapped.
{T}: Add {C}.
{2}{C}, {T}, Sacrifice Mirrorpool: Copy target instant or sorcery spell you control. You may choose new targets for the copy.
{4}{C}, {T}, Sacrifice Mirrorpool: Create a token that's a copy of target creature you control.