Mortuary + Narcomoeba + Grinding Station + Mycosynth Lattice

Mortuary

Narcomoeba

Grinding Station

Mycosynth Lattice

How it works

1. Activate Grinding Station by tapping it and sacrificing Narcomoeba, targeting yourself.
2. When Narcomoeba dies, Mortuary triggers, putting Narcomoeba on top of your library from your graveyard.
3. Resolve the Grinding Station ability, causing you to mill three cards.
4. Narcomoeba triggers, returning itself to the battlefield from your graveyard.
5. When Narcomoeba enters the battlefield, Grinding Station triggers, untapping Grinding Station.
6. Repeat.