Turn Against

Devoid (This card has no color.)
Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.

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.

Molten Nursery

Devoid (This card has no color.)
Whenever you cast a colorless spell, Molten Nursery deals 1 damage to any target.

Processor Assault

Devoid (This card has no color.)
As an additional cost to cast this spell, put a card an opponent owns from exile into that player's graveyard.
Processor Assault deals 5 damage to target creature.

Unknown Shores

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Mountain

Void Shatter

Devoid (This card has no color.)
Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Kozilek's Sentinel

Devoid (This card has no color.)
Whenever you cast a colorless spell, Kozilek's Sentinel gets +1/+0 until end of turn.

Vile Aggregate

Devoid (This card has no color.)
Vile Aggregate's power is equal to the number of colorless creatures you control.
Trample
Ingest (Whenever this creature deals combat damage to a player, that player exiles the top card of their library.)

Island

Vestige of Emrakul

Gravity Negator

Devoid (This card has no color.)
Flying
Whenever Gravity Negator attacks, you may pay {C}. If you do, another target creature gains flying until end of turn. ({C} represents colorless mana.)

Thought Harvester

Devoid (This card has no color.)
Flying
Whenever you cast a colorless spell, target opponent exiles the top card of their library.

Reality Hemorrhage

Devoid (This card has no color.)
Reality Hemorrhage deals 2 damage to any target.

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.

Walker of the Wastes

({C} represents colorless mana.)
Trample
Walker of the Wastes gets +1/+1 for each land you control named Wastes.

Wastes

Conduit of Ruin

When you cast this spell, you may search your library for a colorless creature card with mana value 7 or greater, reveal it, then shuffle and put that card on top.
The first creature spell you cast each turn costs {2} less to cast.

Spell Shrivel

Devoid (This card has no color.)
Counter target spell unless its controller pays {4}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Herald of Kozilek

Devoid (This card has no color.)
Colorless spells you cast cost {1} less to cast.

Deepfathom Skulker

Devoid (This card has no color.)
Whenever a creature you control deals combat damage to a player, you may draw a card.
{3}{C}: Target creature can't be blocked this turn. ({C} represents colorless mana.)