Evereth by sacrificing the legendary creature with flying.
When the creature dies,
Jackdaw Savior triggers, returning
Loyal Retainers from your graveyard to the battlefield.
Resolve the
Evereth ability, putting a +1/+1 counter on it.
Activate
Loyal Retainers by sacrificing it, returning the legendary creature with flying from your graveyard to the battlefield.
Repeat.
Notes
If you have a way to kill
Evereth and ({1} magic symbol) ({BR} magic symbol) available, you can do so after putting a significant amount of +1/+1 counters on it to deal damage to each opponent using its second ability.
Results
Infinite +1/+1 counters on a creature.
Infinite creature ETB.
Infinite creature LTB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Infinite damage.
Metadata
In 0 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).