Activate Goblin Warrens by paying {2}{R} and sacrificing two Goblins, creating three 1/1 Goblin creature tokens.
When the Goblins enter the battlefield, Mana Echoes triggers three times, adding {C}{C}{C} for each Goblin you control.
Activate Skirk Prospector by sacrificing a Goblin, adding {R}.
Repeat.

Infinite LTB

Infinite ETB

Infinite sacrifice triggers

Infinite death triggers

Infinite colorless mana

Goblin Warrens

Mana Echoes

Skirk Prospector

Activate Goblin Warrens by paying {2}{R} and sacrificing two Goblins, creating three 1/1 Goblin creature tokens.
When the Goblins enter the battlefield, Mana Echoes triggers three times, adding {C}{C}{C} for each Goblin you control.
Activate Phyrexian Altar by sacrificing a Goblin, adding {R}.
Repeat.

Phyrexian Altar

Activate Goblin Warrens by paying {2}{R} and sacrificing two Goblins, creating six 1/1 Goblin creature tokens.
Activate Skirk Prospector three times by sacrificing three Goblins, adding {2}{R}.
Repeat.

Infinite creature tokens

Infinite red mana

Parallel Lives

Activate Goblin Warrens by paying {2}{R} and sacrificing two Goblins, creating three 1/1 Goblin creature tokens.
When the Goblins enter the battlefield, Mana Echoes triggers three times, adding {C}{C}{C} for each Goblin you control.
Activate Thermopod's second ability by sacrificing a Goblin, adding {R}.
Repeat.

Thermopod

Activate Goblin Warrens by paying {2}{R} and sacrificing two Goblins, creating six 1/1 Goblin creature tokens.
Activate Phyrexian Altar three times by sacrificing three Goblins, adding {2}{R}.
Repeat.

Infinite colored mana

Activate Goblin Warrens by paying {2}{R} and sacrificing two Goblins.
When the Goblins die, Pitiless Plunderer triggers twice, creating two Treasure tokens.
Resolve the Goblin Warrens ability, creating three 1/1 Goblin creature tokens.
When the Goblins enter the battlefield, Mana Echoes triggers three times, adding {C}{C}{C} for each Goblin you control.
Activate a Treasure by tapping and sacrificing it, adding {R}.
Repeat.

Infinite Treasure tokens

Pitiless Plunderer

Activate Goblin Warrens by paying {2}{R} and sacrificing two Goblins.
When the Goblins die, Pitiless Plunderer triggers twice, creating four Treasure tokens.
Resolve the Goblin Warrens ability, creating three 1/1 Goblin creature tokens.
Activate three Treasures by tapping and sacrificing them, adding {2}{R}.
Repeat.

Xorn

Activate Goblin Warrens by paying {2}{R} and sacrificing two Goblins.
When the Goblins die, Pitiless Plunderer triggers four times, creating four Treasure tokens.
Resolve the Goblin Warrens ability, creating three 1/1 Goblin creature tokens.
Activate three Treasures by tapping and sacrificing them, adding {2}{R}.
Repeat.

Roaming Throne

Drivnod, Carnage Dominus

Teysa Karlov

Activate Goblin Warrens by paying {2}{R} and sacrificing two Goblins, creating six 1/1 Goblin creature tokens.
Activate Thermopod's second ability three times by sacrificing three Goblins, adding {2}{R}.
Repeat.

Combos with "Goblin Warrens"