Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Drogskol Reaver

Flying, double strike, lifelink
Whenever you gain life, draw a card.

Shanna, Purifying Blade

Lifelink
At the beginning of your end step, you may pay {X}. If you do, draw X cards. X can't be greater than the amount of life you gained this turn.

Well of Lost Dreams

Whenever you gain life, you may pay {X}, where X is less than or equal to the amount of life you gained. If you do, draw X cards.