Activate the mutated Everquill Phoenix and Kiki-Jiki creature by tapping it, creating a token copy of it with haste.
Repeat.

Infinite death triggers

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite tapped creature tokens

Kiki-Jiki, Mirror Breaker

Everquill Phoenix

Cast Everquill Phoenix for its mutate cost by paying {3}{R}, putting it under or over a non-Human creature you control.
Everquill Phoenix triggers, creating a Feather artifact token.
Cast Maskwood Nexus by paying {4}.
Activate Thermopod by sacrificing Specimen Collector, adding {R}.
When Specimen Collector dies, its second ability triggers, creating a copy of the Feather token.
Activate a Feather by paying {1} and sacrificing it, returning Specimen Collector from your graveyard to the battlefield.
When Specimen Collector enters the battlefield, its first ability triggers, creating a 1/1 Squirrel and a 0/3 Crab creature token.
Repeat from step 4.

Infinite red mana

Infinite creature tokens

Specimen Collector

Thermopod

Maskwood Nexus

Cast Everquill Phoenix for its mutate cost by paying {3}{R}, mutating it over or under a non-Human creature you control.
Everquill Phoenix triggers, creating a Feather artifact token.
Cast Astral Dragon by paying {6}{U}{U}.
When Astral Dragon enters the battlefield, it triggers, creating two copies of the Feather token that are 3/3 Dragon creatures.
Activate Thermopod by sacrificing Astral Dragon, adding {R}.
Activate a Feather by paying {1} and sacrificing it, returning Astral Dragon from your graveyard to the battlefield.
Repeat from step 4.

Infinite creature token copies of all noncreature permanents

Infinite recursion of creature cards in your graveyard

Astral Dragon

Ashes of the Fallen

Cast Everquill Phoenix for its mutate cost by paying {3}{R}, putting it under or over a non-Human creature you control.
Everquill Phoenix triggers, creating a Feather artifact token.
Cast Maskwood Nexus by paying {4}.
Activate Ghired by tapping it, creating a copy of the Feather token.
Activate Thermopod by sacrificing Ghired, adding {R}.
Activate a Feather by paying {1} and sacrificing it, returning Ghired from your graveyard to the battlefield.
Repeat from step 4.

Ghired, Mirror of the Wilds

Combos with "Everquill Phoenix"