Aerie Ouphes and without a -1/-1 counter on it and
Aerie Ouphes with a +1/+1 counter on it).
Steps
Activate
Dominion Saboteur by sacrificing it.
When
Dominion Saboteur dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it. As it enters, choose to have it copy
Aerie Ouphes, and then also enter with a +1/+1 counter on it.
Resolve the
Dominion Saboteur ability from step 1.
Repeat.
Results
Infinite creature ETB.
Infinite creature LTB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).