Valkyrie's Call, Simulacrum Synthesizer, and Ashnod's Altar

Prerequisites

• Valkyrie's Call on the battlefield
• Simulacrum Synthesizer on the battlefield
• Ashnod's Altar on the battlefield

Steps

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

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite colorless mana
• Infinite tapped creature tokens