The Sibsig Ceremony + Myr Retriever + Scrap Trawler + Temur Battlecrier

The Sibsig Ceremony

Myr Retriever

Scrap Trawler

Temur Battlecrier

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.
8. Cast the artifact creature in your hand by paying 0.
9. When the artifact creature enters, The Sibsig Ceremony triggers, destroying the creature and creating a 2/2 Zombie Druid creature token.
10. When the creature dies, Scrap Trawler triggers, returning Myr Retriever from your graveyard to your hand.
11. Cast Myr Retriever by paying 0.
12. When Myr Retriever enters, The Sibsig Ceremony triggers, destroying Myr Retriever and creating a 2/2 Zombie Druid creature token.
13. When Myr Retriever dies, it and Scrap Trawler trigger.
14. Resolve the Myr Retriever trigger, returning the artifact creature cast in step 1 from your graveyard to your hand.
15. Reoslve the Scrap Trawler trigger, returning nothing.
16. Repeat.