Y'mera The Void Weaver

Eminence — As long as Y'mera is in the
command zone or on the battlefield, Wastes you control can be tapped for a mana of any color.
This mana can only be used for spells with
Devoid and activated abilities from colorless
source you control.
{w}{u}{b}{r}{g}, {t}: Exile the top two cards of each opponent's library. Then, you may cast a spell
from among cards in exile without paying its cost.