Sai, Master Thopterist + Myr Retriever + Scrap Trawler + Ashnod's Altar

Sai, Master Thopterist

Myr Retriever

Scrap Trawler

Ashnod's Altar

How it works

1. Activate Ashnod's Altar by sacrificing Scrap Trawler, adding CC.
2. When Scrap Trawler dies, it triggers, returning Myr Retriever from your graveyard to your hand.
3. Cast Myr Retriever by paying 2.
4. Sai triggers, creating a 1/1 Thopter artifact creature token.
5. Activate Ashnod's Altar twice by sacrificing the Thopter and Myr Retriever, adding CCCC.
6. When Myr Retriever dies, it triggers, returning Scrap Trawler from your graveyard to your hand.
7. Cast Scrap Trawler by paying 3.
8. Sai triggers, creating a 1/1 Thopter artifact creature token.
9. Repeat.

This clever loop works by feeding artifacts into Ashnod's Altar to generate the mana needed to recast them, all while relying on Scrap Trawler and Myr Retriever to constantly rescue each other from the graveyard. As you recast your artifacts, Sai, Master Thopterist eagerly chips in by churning out a steady stream of Thopter tokens, which can either be sacrificed for extra mana to keep the engine going or left behind to swarm the board. Because Scrap Trawler's recursive trigger scales dynamically based on mana values, this setup smoothly loops your key pieces indefinitely to generate an unstoppable army and infinite mana.