Cast an artifact in your hand by paying {0}.
Teshar triggers, returning Nurturing Pixie from your graveyard to the battlefield.
When Nurturing Pixie enters, it triggers, returning another artifact that can be cast for {0} from the battlefield to your hand.
Resolve the artifact spell cast in step 1.
Activate Ashnod's Altar by sacrificing Nurturing Pixie
Repeat.

Infinite artifact ETB

Infinite artifact LTB

Infinite creature ETB

Infinite creature LTB

Infinite colorless mana

Infinite death triggers

Infinite creature sacrifice triggers

Infinite storm count

Artifact Castable for {0} that survives

Teshar, Ancestor's Apostle

Ashnod's Altar

Nurturing Pixie

Activate any number of creatures you control by tapping them, adding at least enough mana to cast Nurturing Pixie.
Cast Nurturing Pixie by paying its mana cost.
When Nurturing Pixie enters the battlefield, it, Clement and Intruder Alarm trigger.
Resolve the Clement trigger, returning nothing to your hand.
Resolve the Nurturing Pixie trigger, returning the other creature with greater mana value from the battlefield to your hand.
Resolve the Intruder Alarm trigger, untapping all creatures.
Activate any number of creatures you control by tapping them, adding at least enough mana to cast the creature returned to your hand.
Cast the creature by paying its mana cost.
When the creature enters the battlefield, Clement and Intruder Alarm trigger.
Resolve the Clement trigger, returning Nurturing Pixie from the battlefield to your hand.
Resolve the Intruder Alarm trigger, untapping all creatures.
Repeat.

Infinite mana creatures you control can produce

Infinite untap of creatures

Clement, the Worrywort

Intruder Alarm

Activate a basic Plains by tapping it, adding {W}.
Cast Nurturing Pixie by paying {W}.
When Nurturing Pixie enters the battlefield, it triggers.
Holding priority, activate Earthcraft by tapping Nurturing Pixie, untapping the Plains.
Resolve the Nurturing Pixie trigger, returning it to your hand from the battlefield, as it is not a Faerie due to Conspiracy.
Repeat.

Earthcraft

Conspiracy

Cast Nethroi either from your hand or from the command zone for its mutate cost by paying {4}{G/W}{B}{B}, putting it under a non-Human creature you control.
Nethroi triggers, returning Nurturing Pixie and Mitotic Slime from your graveyard to the battlefield.
When Nurturing Pixie enters, it triggers, returning Nethroi from the battlefield to your hand.
Activate Phyrexian Altar twice by sacrificing Nurturing Pixie and Mitotic Slime, adding {B}{B}.
When Mitotic Slime dies, it triggers, creating two 2/2 Ooze creature tokens.
Activate Phyrexian Altar twice by sacrificing the Oozes, adding {1}{G/W}.
When the Oozes die, they trigger, creating four 1/1 Ooze creature tokens.
Activate Phyrexian Altar three times by sacrificing three Oozes, adding {3}.
Repeat.

Combos with "Nurturing Pixie"