When End of Days enters the battlefield and at the beginning of your upkeep, each player exiles the top thirteen cards of his or her library.
You may play cards exiled with End of Days for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.
See Challenge # 102.
Hmm. "Draw" 13 cards per turn, but you can only play the ones you can afford. Certainly needs to cost more than Colfenor's Plans, but I think
is excessive. I'd say this is somewhat comparable to Damia, Sage of Stone, and
-
would probably do.