Wicked Gardener

{u}{b}{g}, {t}: Reveal cards from the top of your library until you reveal a land this way. Put that land onto the battlefield and put the rest of those cards into your graveyard.
{b/g}{g/u}{u/b}, {t}: Return a land from your graveyard to the battlefield tapped, then sacrifice it unless you exile cards from your graveyard equal to the number of colors of mana it can produce.