Goblin Miner

When Goblin Miner enters the battlefield, open a Magic: The Gathering booster pack, choose three cards from it, and exile them. You may cast those cards from exile. You may spend mana as if it were mana of any color to cast those cards. When Goblin Miner dies, exile it from your graveyard.
For every 100 useless goblins, there is that one good goblin who can get you what you want.