Valkyrie's Call + Simulacrum Synthesizer + Grinding Station

Valkyrie's Call

Simulacrum Synthesizer

Grinding Station

How it works

1. Cast the Vehicle by paying its mana cost.
2. When the Vehicle enters the battlefield, Grinding Station and Simulacrum Synthesizer trigger.
3. Resolve the Grinding Station trigger, untapping it.
4. Resolve the Simulacrum Synthesizer trigger, creating a 0/0 Construct artifact creature token that gets +1/+1 for each artifact you control.
5. When the Construct enters the battlefield, Grinding Station triggers, untapping Grinding Station.
6. Activate the Vehicle's crew ability by tapping the Construct, causing the Vehicle to become an artifact creature until end of turn.
7. Activate Grinding Station by tapping it and sacrificing the Vehicle.
8. When the Vehicle dies, Valkyrie's Call triggers, returning the Vehicle from your graveyard to the battlefield. It will not be an Angel because the Vehicle is no longer a creature and cannot gain creature types.
9. Repeat steps 2 through 5 one additional time.
10. Resolve the Grinding Station ability from step 7.
11. Repeat from step 6.

This intricate loop turns the continuous rebirth of a crewable Vehicle into an engine for infinite carnage, utilizing Simulacrum Synthesizer to manufacture massive Construct tokens whenever a heavy artifact enters the battlefield. As those tokens arrive, Grinding Station obligingly untaps itself due to its own artifact-triggered ability, ready to sacrifice your newly crewed Vehicle for its milling effect. When that Vehicle perishes, Valkyrie's Call immediately rescues it from the graveyard and returns it directly to the battlefield with a bonus +1/+1 counter. By cycling the Vehicle in and out of play this way, you continuously trigger the Synthesizer and the Station to mill away your opponents' entire libraries.