Activate Ashnod's Altar by sacrificing the nontoken creature, adding {C}{C}.
When the creature dies, Mortuary triggers, putting the creature from your graveyard onto the top of your library.
Cast the creature by paying its mana cost.
Repeat.

Infinite LTB

Infinite ETB

Infinite sacrifice triggers

Infinite death triggers

Infinite colorless mana

Infinite storm count

Mortuary

Ashnod's Altar

Augur of Autumn

Activate Ashnod's Altar by sacrificing the creature that can be cast using {C}{C}, adding {C}{C}.
When the creature dies, Mortuary triggers, putting the creature from your graveyard onto the top of your library.
Cast the creature from the top of your library by paying its mana cost.
Repeat.

Creature That Can Be Cast Using {C}{C}

Activate the Sliver that can be cast using {B}{B} by sacrificing it, adding {B}{B}.
The Sliver is put onto the top of your library instead of into your graveyard due to the replacement effect given to it by Pulmonic Sliver.
Cast the Sliver from the top of your library by paying its mana cost.
Repeat.

Sliver That Can Be Cast Using {B}{B}

Pulmonic Sliver

Basal Sliver

Activate Viscera Seer by sacrificing the nontoken creature.
When the creature dies, Mortuary and Pitiless Plunderer trigger.
Resolve the Mortuary trigger, putting the creature from your graveyard onto the top of your library.
Resolve the Pitiless Plunderer trigger, creating a Treasure token.
Resolve the Viscera Seer ability.
Activate the Treasure by tapping and sacrificing it, adding one mana of any color.
Cast the creature from the top of your library by paying its mana cost
Repeat.

Infinite scry 1

Pitiless Plunderer

Viscera Seer

Activate Phyrexian Altar by sacrificing Golgari Thug, adding {B}.
When Golgari Thug dies, it triggers, returning it from your graveyard to the top of your library.
Wan Shi Tong's second ability triggers, creating two 1/1 Spirit creature tokens.
Activate Phyrexian Altar by sacrificing a Spirit, adding {1}.
Cast Golgari Thug from the top of your library by paying {1}{B}.
Repeat.

Infinite colored mana

Infinite creature tokens

Wan Shi Tong, All-Knowing

Golgari Thug

Phyrexian Altar

Cast Charismatic Conqueror from the top of your library by paying {1}{W}.
Charismatic Conqueror's demonstrate ability triggers, causing you and an opponent to copy it.
Resolve the opponent's copy of Charismatic Conqueror, and then resolve your copy of Charismatic Conqueror.
When your Charismatic Conqueror token enters the battlefield,  the opponent's Charismatic Conqueror triggers, causing you to tap your Charismatic Conqueror token.
Resolve the original Charismatic Conqueror spell.
When the nontoken Charismatic Conqueror enters the battlefield, the opponent's Charismatic Conqueror triggers, causing you to not tap the nontoken Charismatic Conqueror, and causing the opponent to create a 1/1 Vampire creature token.
When the opponent's Vampire token enters the battlefield, both Charismatic Conquerors you control trigger, causing you to create at least one 1/1 Vampire creature token.
When your Vampire token enters the battlefield, the opponent's Charismatic Conqueror triggers, causing you to not tap the Vampire token, and causing the opponent to create a 1/1 Vampire creature token.
Repeat from step 7.

Infinite ETB for target opponent

Infinite creature tokens for target opponent

Charismatic Conqueror

The Twelfth Doctor

Combos with "Augur of Autumn"