Alela, Artful Provocateur + Cloudstone Curio + Shield Sphere + Ornithopter

Alela, Artful Provocateur

Cloudstone Curio

Shield Sphere

Ornithopter

How it works

1. Cast Shield Sphere by paying 0.
2. Alela triggers, creating a 1/1 Faerie creature token.
3. The Faerie enters the battlefield, triggering Cloudstone Curio, returning Ornithopter from the battlefield to your hand.
4. Cast Ornithopter by paying 0.
5. Alela triggers, creating a 1/1 Faerie creature token.
6. The Faerie enters the battlefield, triggering Cloudstone Curio, returning Shield Sphere from the battlefield to your hand.
7. Repeat.