The Jolly Balloon Man in exile (The Jolly Balloon Man exiled by Agatha's Soul Cauldron).
All other permanents on the battlefield.
Midnight Guard has at least one +1/+1 counter on it.
Midnight Guard does not have summoning sickness.
You control at least one mana-producing land.
Steps
Activate up to five lands by tapping them, adding at least ({1} magic symbol) .
Activate Midnight Guard using The Jolly Balloon Man's ability by paying ({1} magic symbol) and tapping it, creating a token copy of Peregrine Drake that is a 1/1 Balloon with flying and haste in addition to its other types.
When the Peregrine Drake token enters the battlefield, it and Midnight Guard trigger.
Resolve the Peregrine Drake token's trigger, untapping up to five lands.
Resolve the Midnight Guard trigger, untapping it.
Repeat.
Notes
Once you have infinite mana, you may target any other creature using step 1 instead.
Results
Infinite LTB.
Infinite ETB.
Infinite sacrifice triggers.
Infinite death triggers.
Infinite creature tokens with haste.
Infinite token copies of each creature you control with haste except Midnight Guard.