Activate Devoted Druid's first ability by tapping it, adding {G}.
Activate Devoted Druid's second ability by putting a -1/-1 counter on it.
Flourishing Defenses triggers, creating a 1/1 Elf Warrior creature token.
The Elf Warrior enters the battlefield, triggering Ivy Lane Denizen, putting a +1/+1 counter on Devoted Druid.
Resolve the Devoted Druid ability from step 2, untapping it.
Repeat.

Infinite creature tokens

Infinite ETB

Infinite green mana

Ivy Lane Denizen

Devoted Druid

Flourishing Defenses

Activate Volrath by paying {1}, causing it to become a copy of Grim Poppet until your next turn.
Activate Grim Poppet by removing a -1/-1 counter from it, putting a -1/-1 counter on Volrath.
Flourishing Defenses triggers, creating a creature token.
Activate Volrath by removing a -1/-1 counter from it, putting a -1/-1 counter on Grim Poppet.
Flourishing Defenses triggers, creating a creature token.
Repeat from step 2.

Volrath, the Shapestealer

Grim Poppet

Activate Skeleton Ship by tapping it, putting a -1/-1 counter on target creature.
Flourishing Defenses triggers, creating a creature token.
When the creature token enters, Intruder Alarm triggers, untapping all creatures.
Repeat.

Infinite LTB

Infinite death triggers

Infinite mana creatures you control can produce

Infinite untap of all creatures

Infinite -1/-1 counters

Skeleton Ship

Intruder Alarm

Activate Grim Poppet by removing a -1/-1 counter from it, putting a -1/-1 counter on Sakashima of a Thousand Faces.
Flourishing Defenses triggers, creating a creature token.
Activate Sakashima of a Thousand Faces by removing a -1/-1 counter from it, putting a -1/-1 counter on Grim Poppet.
Flourishing Defenses triggers, creating a creature token.
Repeat.

Sakashima of a Thousand Faces

Activate Xavier Sal's second ability by tapping it and sacrificing another creature, putting a +1/+1 counter on it.
Activate Xavier Sal using Devoted Druid's second ability by putting a -1/-1 counter on it.
Flourishing Defenses triggers, creating a creature token.
Resolve the Xavier Sal ability, untapping it.
Repeat.

Infinite sacrifice triggers

Infinite proliferate

Xavier Sal, Infested Captain

Agatha's Soul Cauldron

Activate Skeleton Ship by tapping it, putting a -1/-1 counter on target creature with toughness equal to 1.
The creature dies as a state-based action due to having zero or less toughness, triggering Flourishing Defenses and Skeleton Ship.
Resolve the Flourishing Defenses trigger, creating a creature token.
Resolve the Skeleton Ship trigger, untapping it.
Repeat.

Thornbite Staff

Activate a basic land by tapping it, adding {1}.
Activate Earthcraft by tapping Loporrit Scout, untapping a basic land.
Acitvate Loporrit Scout by paying {1} and putting a -1/-1 counter on it.
Flourishing Defenses triggers, creating a creature token.
When the creature token enters the battlefield, Loporrit Scout triggers, giving Loporrit Scout +1/+1 until end of turn.
Resolve the Loporrit Scout ability from step 1, untapping it.
Repeat.

Infinite mana basic lands you control can produce

Infinite untap of basic lands you control

Loporrit Scout

Sinking Feeling

Earthcraft

Acitvate Loporrit Scout by paying {1} and putting a -1/-1 counter on it.
Flourishing Defenses triggers, creating a creature token.
When the creature token enters the battlefield, Loporrit Scout triggers, giving Loporrit Scout +1/+1 until end of turn.
Resolve the Loporrit Scout ability from step 1, untapping it.
Activate Phyrexian Altar by sacrificing the creature token, adding {1}.
Repeat.

Combos with "Flourishing Defenses"