Cast Maddening Cacophony with kicker by paying {4}{U}{U}, causing each opponent to mill their entire library.

Infinite mill

Maddening Cacophony

Bruvac the Grandiloquent

Cast Traumatize by paying {3}{U}{U}, causing target opponent with an even library size to mill their entire library.

Infinite mill for target opponent

Traumatize

Cast Cut Your Losses by paying {4}{U}{U}, targeting any player with an even library size.
Cut Your Losses' casualty ability triggers, allowing you to sacrifice a creature with power two or greater to create a copy of Cut Your Losses, targeting any other player with an even library size.
Resolve each Cut Your Losses, causing one or two players to mill their entire library.

Infinite mill for up to two target players

Cut Your Losses

Declare Terisian Mindbreaker as an attacker.
Terisian Mindbreaker triggers, causing the defending player to mill their library.

Terisian Mindbreaker

Declare Fleet Swallower as an attacker, attacking any opponent with an even library size.
Fleet Swallower triggers, causing the opponent to mill their entire library.

Fleet Swallower

Cast Singularity Rapture by paying {3}{U}{B}{B}, destroying all creatures and then causing any number of target players to mill a number of cards equal to half their library, rounded down, times two.

Infinite self-mill

Singularity Rupture

Declare Lord Xander as an attacker, attacking any opponent with an even library size.
Lord Xander's second ability triggers, causing the opponent to mill their entire library.

Lord Xander, the Collector

Cast Blood Pet by paying {B}.
When Blood Pet enters the battlefield, Altar of the Brood triggers.
Holding priority, activate Blood Pet by sacrificing it, adding {B}.
Resolve the Altar of the Brood trigger, causing each opponent to mill two cards due to Bruvac.
If an opponent mills a nonland card, The Wise Mothman triggers, putting a +1/+1 counter on Evolution Witness.
Evolution Witness triggers, returning Blood Pet from your graveyard to your hand.
Repeat.

Combos with "Bruvac the Grandiloquent"