The Sibsig Ceremony + Myr Retriever + Scrap Trawler + Shuri, Wakandan Inventor

The Sibsig Ceremony

Myr Retriever

Scrap Trawler

Shuri, Wakandan Inventor

How it works

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