Myr Retriever + Junk Diver + Grinding Station + Mycosynth Golem

Myr Retriever

Junk Diver

Grinding Station

Mycosynth Golem

How it works

1. Activate Grinding Station by tapping it and sacrificing Junk Diver.
2. When Junk Diver dies, it triggers, returning Myr Retriever from your graveyard to your hand.
3. Resolve the Grinding Station ability, causing target player to mill three cards.
4. Cast Myr Retriever by paying 0.
5. When Myr Retriever enters the battlefield, Grinding Station triggers, untapping Grinding Station.
6. Activate Grinding Station by tapping it and sacrificing Myr Retriever.
7. When Myr Retriever dies, it triggers, returning Junk Diver from your graveyard to your hand.
8. Resolve the Grinding Station ability, causing target player to mill three cards.
9. Cast Junk Diver by paying 0.
10. When Junk Diver enters the battlefield, Grinding Station triggers, untapping Grinding Station.
11. Repeat.