Eldrazi Aggressor

Devoid (This card has no color.)
Eldrazi Aggressor has haste as long as you control another colorless creature.

Flayer Drone

Devoid (This card has no color.)
First strike
Whenever another colorless creature you control enters, target opponent loses 1 life.

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.

Forerunner of Slaughter

Devoid (This card has no color.)
{1}: Target colorless creature gains haste until end of turn.

Akoum Refuge

Akoum Refuge enters tapped.
When Akoum Refuge enters, you gain 1 life.
{T}: Add {B} or {R}.

Coat with Venom

Target creature gets +1/+2 and gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Eldrazi Obligator

Devoid (This card has no color.)
When you cast this spell, you may pay {1}{C}. If you do, gain control of target creature until end of turn, untap that creature, and it gains haste until end of turn. ({C} represents colorless mana.)
Haste

Wastes

Emrakul's Hatcher

When Emrakul's Hatcher enters, create three 0/1 colorless Eldrazi Spawn creature tokens. They have "Sacrifice this creature: Add {C}."

Mountain

Cast Down

Immobilizer Eldrazi

Devoid (This card has no color.)
{2}{C}: Each creature with toughness greater than its power can't block this turn. ({C} represents colorless mana.)