Enchantment - Quest
(Add a quest counter as this enters. Sacrifice after 6.)
Whenever you cast a permanent spell, add a quest counter.
1, 2, 3, 4, 5, 6 — Choose a color that hasn't been chosen. Search your library for a permanent card that's exactly that color, reveal it, and put it into your hand. Then shuffle.
Exile Collect the World Stones. For the rest of the game, you may spend mana as though it were mana of any color.