The Sibsig Ceremony + Myr Retriever + Semblance Anvil + Workshop Assistant

The Sibsig Ceremony

Myr Retriever

Semblance Anvil

Workshop Assistant

How it works

1. Cast Workshop Assistant by paying 0.
2. When Workshop Assistant enters the battlefield, The Sibsig Ceremony triggers, destroying Workshop Assistant and creating a 2/2 Zombie Druid creature token.
3. When Workshop Assistant dies, it triggers, returning Myr Retriever from your graveyard to your hand.
4. Cast Myr Retriever by paying 0.
5. When Myr Retriever enters the battlefield, The Sibsig Ceremony triggers, destroying Myr Retriever and creating a 2/2 Zombie Druid creature token.
6. When Myr Retriever dies, it triggers, returning Workshop Assistant from your graveyard to your hand.
7. Repeat.