Quintorius, Field Historian, Extractor Demon, Ashnod's Altar, and Barkform Harvester

Prerequisites

• Quintorius, Field Historian on the battlefield
• Extractor Demon on the battlefield
• Ashnod's Altar on the battlefield
• Barkform Harvester on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing another creature, adding
2. When the creature dies, Extractor Demon triggers, causing you to mill two cards if your graveyard is empty, or causing an opponent to mill two cards otherwise
3. If your library is empty, activate Barkform Harvester by paying , putting a card from your graveyard onto the bottom of your library
4. Quintorius triggers, creating a 3/2 Spirit creature token
5. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite mill
• Infinite self-mill
• Near-infinite colorless mana