Jace in hand or on the battlefield or in your library.
Ad Nauseam and
Angel's Grace in hand.
Mana Needed
({3} magic symbol) ({W} magic symbol) ({B} magic symbol) ({B} magic symbol) plus an additional ({1} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) available if
Jace is not on the battlefield available.
Steps
Cast
Angel's Grace by paying ({W} magic symbol) , preventing you from losing the game this turn.
Cast
Ad Nauseam by paying ({3} magic symbol) ({B} magic symbol) ({B} magic symbol) .
Resolve
Ad Nauseam, revealing the top card of your library, putting that card into your hand and losing life equal to that card's mana value.
Repeat the process in step 3 until you have an empty library.
If
Jace is in your hand, cast it by paying ({1} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) .
Activate
Jace's first loyalty ability by putting a loyalty counter on it, causing target player to mill two cards and you to win the game due to drawing from an empty library.
Results
Infinite card draw.
Win the game.
Metadata
In 437 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Ruthless (Bracket 4+).