Retrofitter Foundry, Krark-Clan Ironworks, Clock of Omens, and Elspeth, Storm Slayer

Prerequisites

• Retrofitter Foundry on the battlefield
• Krark-Clan Ironworks on the battlefield
• Clock of Omens on the battlefield
• Elspeth, Storm Slayer on the battlefield
• undefined available

Steps

1. Activate Retrofitter Foundry's second ability by paying and tapping it, creating two 1/1 Servo artifact creature tokens
2. Activate Clock of Omens by tapping the Servos, untapping Retrofitter Foundry
3. Activate Ashnod's Altar by sacrificing a Servo, adding
4. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite colorless mana
• Infinite creature tokens
• Infinite mana artifacts you control can produce
• Infinite untap of artifacts you control