Cast Dread Return by paying its mana cost
Holding priority, cast Dualcaster Mage by paying its mana cost.
When Dualcaster Mage enters, it triggers, targeting Dread Return.
Holding priority, activate Viscera Seer by sacrificing Dualcaster Mage.
Resolve the Dualcaster Mage trigger, copying Dread Return
Resolve the Dread Return copy, returning Dualcaster Mage from your graveyard to the battlefield.
Repeat from step 3.

Infinite creature ETB

Infinite creature LTB

Infinite death triggers

Infinite magecraft triggers

Infinite creature sacrifice triggers

Infinite scry 1

Viscera Seer

Dualcaster Mage

Dread Return

Activate Nomads en-Kor, targeting Cephalid Illusionist.
Mill 3.
Repeat this process until you mill your entire library.
When you mill Narcomoeba, put it on the battlefield.
Flashback Dread Return, sacrificing Nomads en-Kor, Cephalid Illusionist, and Narcomoeba, targeting Thassa's Oracle.
Resolve Thassa's Oracle's trigger with no cards in your library.

Infinite self-mill

Win the game

Cephalid Illusionist

Nomads en-Kor

Narcomoeba

Thassa's Oracle

Cast Sacrifice by paying {B} and sacrificing Scholar of the Ages, adding seven {B}.
Cast Dread Return by paying {2}{B}{B}, returning Scholar of the Ages from your graveyard to the battlefield.
Scholar of the Ages triggers, returning Sacrifice and Dread Return from your graveyard to your hand.
Repeat.

Infinite black mana

Infinite storm count

Return all instant and sorcery cards from your graveyard to your hand

Scholar of the Ages

Sacrifice

Cast Burnt Offering by paying {B} and sacrificing Scholar of the Ages, adding seven mana in any combination of {B} and/or {R}.
Cast Dread Return by paying {2}{B}{B}, returning Scholar of the Ages from your graveyard to the battlefield.
Scholar of the Ages triggers, returning Burnt Offering and Dread Return from your graveyard to your hand.
Repeat.

Infinite red mana

Burnt Offering

Combos with "Dread Return"