Cloudstone Curio + Crimson Kobolds + Kobolds of Kher Keep

Cloudstone Curio

Crimson Kobolds

Kobolds of Kher Keep

How it works

1. Cast Kobolds of Kher Keep by paying 0.
2. When Kobolds of Kher Keep enters. Cloudstone Curio triggers, returning Crimson Kobolds from the battlefield to your hand.
3. Cast Crimson Kobolds by paying 0.
4. When Crimson Kobolds enters, Cloudstone Curio triggers, returning Kobolds of Kher Keep from the battlefield to your hand.
5. Repeat.