Activate Ashnod's Altar by sacrificing Tenacious Dead, adding {C}{C}.
When Tenacious Dead dies, it and Pitiless Plunderer trigger.
Resolve the Pitiless Plunderer trigger, creating a Treasure token.
Activate that Treasure token by tapping and sacrificing it, adding {B}.
Resolve the Tenacious Dead trigger, paying {1}{B} to return it to the battlefield from your graveyard.
Repeat.

Infinite colorless mana

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite death triggers

Tenacious Dead

Ashnod's Altar

Pitiless Plunderer

Activate Viscera Seer by sacrificing Tenacious Dead.
When Tenacious Dead dies, it, Pawn of Ulamog, and Pitiless Plunderer trigger.
Resolve the Pitiless Plunderer trigger, creating a Treasure token.
Resolve the Pawn of Ulamog trigger, creating a creature token.
In response to the remaining trigger, activate Viscera Seer by sacrificing the creature token.
When the creature token dies, Pitiless Plunderer triggers, creating a Treasure token.
Resolve the Viscera Seer ability from step 5.
Activate two Treasure tokens by tapping and sacrificing them, adding {B}{B}.
Resolve the Tenacious Dead trigger, paying {1}{B} to return it to the battlefield from your graveyard.
Resolve the Viscera Seer ability from step 1.
Repeat.

Infinite artifact LTB

Infinite colored mana

Infinite scry 1

Viscera Seer

Pawn of Ulamog

Activate Ashnod's Altar by sacrificing Tenacious Dead, adding {C}{C}.
Tenacious Dead dies, causing you to pay {2} to return it from your graveyard to the battlefield tapped.
Repeat.

Mycosynth Lattice

Infinite card draw

Infinite draw triggers

Chromatic Orrery

Activate Krark-Clan Ironworks by sacrificing Tenacious Dead, adding {C}{C}.
Tenacious Dead dies, causing you to pay {2} to return it from your graveyard to the battlefield tapped.
Repeat.

Krark-Clan Ironworks

Activate Fain's first ability by tapping it and sacrificing Tenacious Dead.
 Tenacious Dead dies, triggering itself and Fain.
Resolve the Fain trigger, untapping it.
Resolve the Tenacious Dead trigger, causing you to pay {1}{B} to return it from your graveyard to the battlefield tapped.
Resolve the Fain ability from step 1, putting two +1/+1 counters on Crystalline Crawler.
Activate Crystalline Crawler's first ability twice by removing two counters from it, adding {B}{B}.
Repeat.

Fain, the Broker

Thornbite Staff

Crystalline Crawler

Combos with "Tenacious Dead"