Activate The Unbeatable Squirrel Girl by paying {1}{G}{G}{G}, creating a 1/1 Squirrel creature token for each Squirrel you control.
Activate four Squirrels by tapping them, adding {1}{G}{G}{G}.
Repeat

Infinite ETB

Infinite colored mana

Infinite creature tokens with haste

The Unbeatable Squirrel Girl

Concordant Crossroads

Springleaf Parade

Cast Malevolent Rumble for its escape cost by paying {1}{G} and exiling three other cards from your graveyard, causing you to mill at least three cards and create a 0/1 Eldrazi Spawn creature token.
Activate the Eldrazi Spawn by tapping it, adding {G}.
Activate the Eldrazi Spawn by sacrificing it, adding {C}.
Repeat.

Infinite self-mill

Near-infinite ETB

Near-infinite LTB

Near-infinite death triggers

Near-infinite magecraft triggers

Near-infinite storm count

Underworld Breach

Malevolent Rumble

Cast Abby from the command zone by paying {1}{R}{G} plus commander tax if applicable.
Abby triggers, creating a number of 1/1 Fungus Zombie creature tokens named Cordyceps Infected equal to the amount of mana spent to cast it.
When Abby enters under an opponent's control, Mirror of Life Trapping triggers, exiling Abby.
Choose to return Abby from exile to the command zone.
Activate two Codryceps Infected tokens by tapping them, adding {R}{G}.
Activate Ashnod's Altar by sacrificing a Cordyceps Infected token, adding {C}{C}.
Repeat step 6 until you have enough mana to cast Abby.
Repeat from step 1.

Combos with "Springleaf Parade"