All permanents on the battlefield (Moritte of the Frost as a copy of River Kelpie).
Steps
Activate Bloodflow Connoisseur by sacrificing Moritte of the Frost.
When Moritte of the Frost dies, its persist ability triggers, returning it from your graveyard to the battlefield as a copy of River Kelpie with one +1/+1 counter on it due to its persist ability and its static effect.
When Moritte of the Frost enters the battlefield, it and River Kelpie's first ability triggers, causing you to draw two cards.
Resolve the Bloodflow Connoisseur ability from step 1, putting a +1/+1 counter on it.
Repeat.
Results
Infinite card draw.
Infinite draw triggers.
Near-infinite +1/+1 counters on Bloodflow Connoisseur.