Cast Infested Thrinax by paying {3}{B}{G}.
When Infested Thrinax enters the battlefield, it triggers, causing you to create a number of 1/1 Saproling creature tokens when a nontoken creature you control dies.
Activate Phyrexian Altar by sacrificing Brokkos, adding {1}.
When Brokkos dies, Infested Thrinax triggers, creating six 1/1 Saproling creature tokens.
Activate Phyrexian Altar four times by sacrificing four Saprolings, adding {1}{U/B}{G}{G}.
Cast Brokkos from your graveyard for its mutate cost by paying {2}{U/B}{G}{G}, putting it on top of a Saproling.
Repeat from step 3.

Infinite creature LTB

Infinite creature ETB

Infinite colored mana

Infinite creature sacrifice triggers

Infinite death triggers

Infinite storm count

Infinite creature tokens

Brokkos, Apex of Forever

Infested Thrinax

Phyrexian Altar

Cast Infested Thrinax by paying {3}{B}{G}.
When Infested Thrinax enters the battlefield, it triggers, causing you to create a number of 1/1 Saproling creature tokens when a nontoken creature you control dies.
Activate Ashnod's Altar by sacrificing Brokkos, adding {C}{C}.
When Brokkos dies, Infested Thrinax and Pitiless Plunderer trigger.
Resolve the Infested Thrinax trigger, creating six 1/1 Saproling creature tokens.
Resolve the Pitiless Plunderer trigger, creating a Treasure token.
Activate Ashnod's Altar twice by sacrificing two Saprolings, adding {C}{C}{C}{C}.
When the Saprolings die, Pitiless Plunderer triggers twice, creating two Treasure tokens.
Activate three Treasures by tapping and sacrificing them, adding {U/B}{G}{G}.
Cast Brokkos from your graveyard for its mutate cost by paying {2}{U/B}{G}{G}, putting it on top of a Saproling.
Repeat from step 3.

Infinite artifact ETB

Infinite artifact LTB

Infinite artifact sacrifice triggers

Infinite artifact tokens

Infinite colorless mana

Infinite Treasure tokens

Pitiless Plunderer

Ashnod's Altar

Activate Korozda Guildmage's second ability by paying {2}{B}{G} and sacrificing Brokkos.
When Brokkos dies, Pitiless Plunderer triggers, creating a Treasure token.
Resolve the Korozda Guildmage ability, creating six 1/1 Saproling creature tokens.
Activate Phyrexian Altar by sacrificing a Saproling, adding {1}.
When the Saproling dies, Pitiless Plunderer triggers, creating a Treasure token.
Repeat from step 4 three additional times.
Activate five Treasures by tapping and sacrificing them, adding {U/B}{B}{G}{G}{G}.
Cast Brokkos from your graveyard for its mutate ability by paying {2}{U/B}{G}{G}, putting it on top of a Saproling token.
Repeat.

Korozda Guildmage

Combos with "Brokkos, Apex of Forever"