What's the rarest Magic card in existence?
Power Nine
Ancestral Recall allows the player to draw three cards at an extremely low cost.[10] It originated as part of a set of five cards known as "Boons", one of each color, which gave three of something (e.g. mana, life, damage) for the cost of one mana. Ancestral Recall is the only rare Boon and the only one not to have been reprinted since the Unlimited set.[11]