Mer, Summation of the Oceans

(This Civilization's ability costs are reduced by {1} for each creature on your side of the field that
shares a color type with mana this land can produce.)
{2}, {t}: {u}{b}{g}
4, Sacrifice Mer: Search the top four cards of
your library. Reveal a blue, black, or green spell
from among those cards, and put that card in
your hand. Put the rest of the cards on the
bottom of your library in any order.