Gift of Immortality attached to Child of Alara.

Activate Ashnod's Altar by sacrificing Child of Alara, adding .
Child of Alara dies, triggering itself and Gift of Immortality.
Resolve the Child of Alara trigger, destroying all nonland permanents you don't control due to your permanents having indestructible.
Resolve the Gift of Immortality trigger, returning Child of Alara from your graveyard to the battlefield.
At the beginning of the next end step, Gift of Immortality triggers, returning itself from your graveyard to the battlefield attached to Child of Alara.
Repeat each turn.

Gift of Immortality attached to Child of Alara.

Activate Phyrexian Altar by sacrificing Child of Alara, adding one mana of any color.
Child of Alara dies, triggering itself and Gift of Immortality.
Resolve the Child of Alara trigger, destroying all nonland permanents you don't control due to your permanents having indestructible.
Resolve the Gift of Immortality trigger, returning Child of Alara from your graveyard to the battlefield.
At the beginning of the next end step, Gift of Immortality triggers, returning itself from your graveyard to the battlefield attached to Child of Alara.
Repeat each turn.

Activate Commander's Sphere's first ability by tapping it, adding .
Activate Commander's Sphere's second ability by sacrificing it, causing you to draw a card.
Activate Ashnod's Altar by sacrificing Eternal Witness and Child of Alara, adding .
Child of Alara dies, destroying all nonland permanents.
Cast Faith's Reward by paying , returning all permanent cards put into your graveyard this turn to the battlefield under your control.
Eternal Witness enters the battlefield, returning Faith's Reward from your graveyard to your hand.
Repeat.

Activate Commander's Sphere's first ability by tapping it, adding .
Activate Commander's Sphere's second ability by sacrificing it, causing you to draw a card.
Activate Ashnod's Altar by sacrificing Archaeomancer and Child of Alara, adding .
Child of Alara dies, destroying all nonland permanents.
Cast Faith's Reward by paying , returning all permanent cards put into your graveyard this turn to the battlefield under your control.
Archaeomancer enters the battlefield, returning Faith's Reward from your graveyard to your hand.
Repeat.

Activate Commander's Sphere's first ability by tapping it, adding .
Activate Commander's Sphere's second ability by sacrificing it, causing you to draw a card.
Activate Ashnod's Altar by sacrificing Greenwarden of Murasa and Child of Alara, adding .
Child of Alara and Greenwarden of Murasa die, triggering their abilities.
Resolve the Greenwarden of Murasa trigger, choosing not to exile it.
Resolve the Child of Alara trigger, destroying all nonland permanents.
Cast Faith's Reward by paying , returning all permanent cards put into your graveyard this turn to the battlefield under your control.
Greenwarden of Murasa enters the battlefield, returning Faith's Reward from your graveyard to your hand.
Repeat.