Auramancer + Second Chance + Soulherder + Tidal Barracuda

Auramancer

Second Chance

Soulherder

Tidal Barracuda

How it works

1. At the beginning of your upkeep, Second Chance triggers, causing you to sacrifice it and take an extra turh after this one.
2. At the beginning of your end step, Soulherder's second ability triggers, blinking Auramancer.
3. When Auramancer enters the battlefield, it triggers, returning Second Chance from your graveyard to your hand.
4. Cast Second Chance by paying 2.
5. Repeat each turn.