Fain, the Broker, Intruder Alarm, Pitiless Plunderer, and Carrion Feeder

Prerequisites

• Fain, the Broker on the battlefield
• Intruder Alarm on the battlefield
• Pitiless Plunderer on the battlefield
• Carrion Feeder on the battlefield
• Fain does not have summoning sickness
• You control at least one additional artifact

Steps

1. Activate Fain's third ability by tapping it and sacrificing another artifact, creating a 2/1 Inkling creature token
2. When the Inkling enters the battlefield, Intruder Alarm triggers, untapping all creatures
3. Activate Carrion Feeder by sacrificing the Inkling
4. When the Inkling dies, Pitiless Plunderer triggers, creating a Treasure token
5. Resolve the Carrion Feeder ability, putting a +1/+1 counter on it
6. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite untap of all creatures
• Infinite mana creatures you control can produce
• Infinite +1/+1 counters on Carrion Feeder