Laboratory Maniac and Phyrexian Devourer on the battlefield.
You have a way to draw a card.
Steps
Activate Phyrexian Devourer by exiling the top card of your library.
Repeat step 1 until you have an empty library.
Resolve a Phyrexian Devourer ability, putting a number of +1/+1 counters on it equal to the exiled card's mana value.
If Phyrexian Devourer has a power of at least seven, it triggers, causing you to sacrifice it.
Repeat steps 3-4 until you sacrifice Phyrexian Devourer, thus causing all remaining Phyrexian Devourer abilities to fail to resolve due to having no legal targets.
Draw a card, causing you to win the game due to drawing from an empty library.