The Jolly Balloon Man in exile (The Jolly Balloon Man exiled by Agatha's Soul Cauldron).
All other permanents on the battlefield.
An opponent has lost life this turn
Midnight Guard has at least one +1/+1 counter on it.
Midnight Guard does not have summoning sickness.
({1} magic symbol) available.
Steps
Activate Midnight Guard using The Jolly Balloon Man's ability by paying ({1} magic symbol) and tapping it, creating a token copy of Flamecache Gecko that is a 1/1 Balloon with flying and haste in addition to its other types.
When the Flamecache Gecko token enters the battlefield, it and Midnight Guard trigger.
Once you have infinite mana, you may target any other creature using step 1 instead. You may also use Flamecache Gecko's ability to infinitely rummage.
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.