Cast Doomsday by paying {B}{B}{B}, searching your library and graveyard for Gush, Gitaxian Probe, Lion's Eye Diamond, Yawgmoth's Will and Laboratory Maniac, then exiling the rest of your library and graveyard, putting the aforementioned cards on top of your library in that order, and causing you to lose half your life total, rounded up.
Draw Gush from the top of your library.
Cast Gush by returning two Islands you control from the battlefield to your hand, causing you to draw Gitaxian Probe and Lion's Eye Diamond.
Cast Lion's Eye Diamond by paying {0}.
Cast Gitaxian Probe by paying {U/P}.
Holding priority, activate Lion's Eye Diamond by sacrificing it and discarding your hand, adding {B}{B}{B}.
Resolve Gitaxian Probe, causing you to look at a player's hand and draw Yawgmoth's Will.
Cast Yawgmoth's Will by paying {2}{B}, allowing you to cast spells from your graveyard this turn.
Cast Lion's Eye Diamond from your graveyard by paying {0}.
Activate Lion's Eye Diamond by sacrificing it and discarding your hand, adding {U}{U}{U}.
Lion's Eye Diamond is exiled instead of being put into your graveyard due to Yawgmoth's Will.
Cast Gitaxian Probe from your graveyard by paying {U/P}, causing you to look at a player's hand and draw Laboratory Maniac.
Gitaxian Probe is exiled instead of being put into your graveyard due to Yawgmoth's Will.
Cast Laboratory Maniac by paying {2}{U}.
Cast Gush from your graveyard by returning two Islands you control from the battlefield to your hand, causing you to draw two cards and win the game due to drawing from an empty library.

Win the game

Doomsday

Gush

Gitaxian Probe

Lion's Eye Diamond

Yawgmoth's Will

Laboratory Maniac

Cast Yawgmoth's Will by paying {2}{B}.
Activate Ashnod's Altar by sacrificing Eternal Scourge, adding {C}{C}.
Eternal Scourge is exiled instead of being put into your graveyard due to Yawgmoth's Will.
Cast Eternal Scourge from exile by paying {3}.
Prosper's second ability triggers, creating a Treasure artifact token.
Activate the Treasure by tapping and sacrificing it, adding {1}.
Repeat.

Infinite artifact ETB

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite storm count

Prosper, Tome-Bound

Eternal Scourge

Ashnod's Altar

Cast Yawgmoth's Will by paying {2}{B}, causing all cards put into your graveyard this turn to be exiled.
Activate Ashnod's Altar by sacrificing Squee, adding {C}{C}.
Squee is put into exile instead of your graveyard due to Yawgmoth's Will.
Cast Squee from exile by paying {1}{R}{R}.
Prosper triggers, creating two Treasure tokens.
Activate the Treasure tokens by tapping and sacrificing them, adding {R}{R}.
Repeat from step 2.

Infinite colorless mana

Infinite death triggers

Squee, the Immortal

Xorn

Cast Yawgmoth's Will by paying {2}{B}, causing all cards put into your graveyard this turn to be exiled.
Activate Ashnod's Altar by sacrificing Squee, adding {C}{C}.
Squee is put into exile instead of your graveyard due to Yawgmoth's Will.
Cast Squee from exile by paying {1}{R}{R}.
Prosper triggers, creating a Treasure token.
Activate the Treasure token by tapping and sacrificing it, adding {R}{R}.
Repeat from step 2.

Goldspan Dragon

Combos with "Yawgmoth's Will"