Brotherhood Outcast, Ashnod's Altar, and Kaya's Ghostform

Prerequisites

• Brotherhood Outcast on the battlefield
• Ashnod's Altar on the battlefield
• Kaya's Ghostform on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Brotherhood Outcast
2. When Brotherhood Outcast dies, Kaya's Ghostform triggers, returning Brotherhood Outcast from your graveyard to the battlefield
3. When Brotherhood Outcast enters the battlefield, it triggers, returning Kaya's Ghostform from your graveyard to the battlefield attached to Brotherhood Outcast
4. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite colorless mana