Herald of Kozilek

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

Flayer Drone

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

Cultivator Drone

Devoid (This card has no color.)
{T}: Add {C}. Spend this mana only to cast a colorless spell, activate an ability of a colorless permanent, or pay a cost that contains {C}. ({C} represents colorless mana.)

Azlask, the Swelling Scourge

Whenever Azlask or another colorless creature you control dies, you get an experience counter.
{W}{U}{B}{R}{G}: Creatures you control get +X/+X until end of turn, where X is the number of experience counters you have. Scions and Spawns you control gain indestructible and annihilator 1 until end of turn.

Catacomb Sifter

Devoid (This card has no color.)
When this creature enters, create a 1/1 colorless Eldrazi Scion creature token. It has "Sacrifice this token: Add {C}."
Whenever another creature you control dies, scry 1. (Look at the top card of your library. You may put that card on the bottom.)