Toph, the First Metalbender + Gonti's Aether Heart

Prerequisites

You are able to produce six {E} per turn.

Steps

1. Produce six {E} by any method. This can include using Gonti's Aether Heart by having artifacts enter under your control.
2. At the beginning of your end step, Toph triggers, earthbending Gonti's Aether Heart.
3. Holding priority, activate Gonti's Aether Heart by paying eight {E} and exiling it.
4. Toph triggers, returning Gonti's Aether Heart from exile to the battlefield.
5. When Gonti's Aether Heart enters, it triggers, causing you to get {E}{E}.
6. Resolve the Gonti's Aether Heart ability, causing you to take an extra turn after this one.
7. Repeat.