Activate Ashnod's Altar by sacrificing Wretched Throng, adding {C}{C}.
When Wretched Throng dies, it triggers.
Holding priority, activate Soldevi Digger by paying {2}, putting Wretched Throng from your graveyard onto the bottom of your library.
Resolve the Wretched Throng trigger, putting Wretched Throng from your library into your hand.
Cast Wretched Throng by paying {0}.
Repeat.

Infinite LTB

Infinite ETB

Infinite sacrifice triggers

Infinite death triggers

Infinite storm count

Wretched Throng

Rooftop Storm

Ashnod's Altar

Soldevi Digger

Activate Ashnod's Altar by sacrificing Wretched Throng, adding {C}{C}.
When Wretched Throng dies, it and Pitiless Plunderer trigger.
Holding priority, activate Soldevi Digger by paying {2}, putting Wretched Throng from your graveyard onto the bottom of your library.
Resolve the Pitiless Plunderer trigger, creating a Treasure token.
Resolve the Wretched Throng trigger, putting Wretched Throng from your library into your hand.
Activate the Treasure by tapping and sacrificing it, adding {U}.
Cast Wretched Throng by paying {U} due to The Water Crystal.
Repeat.

Pitiless Plunderer

The Water Crystal

Combos with "Wretched Throng"