Ashnod's Altar, Hofri Ghostforge, and Moorland Rescuer

Prerequisites

• Ashnod's Altar on the battlefield
• Hofri Ghostforge on the battlefield
• Moorland Rescuer on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Moorland Rescuer, adding
2. Moorland Rescuer dies, triggering itself and Hofri Ghostforge
3. Resolve the Hofri Ghostforge trigger, exiling Moorland Rescuer from your graveyard and creating a token copy of Moorland Rescuer that has "When this creature leaves the battlefield, return the exiled card to your graveyard"
4. Resolve the Moorland Rescuer trigger, returning nothing from your graveyard to the battlefield
5. Activate Ashnod's Altar by sacrificing the Moorland Rescuer token, adding
6. The Moorland Rescuer token dies, triggering itself twice
7. Resolve the Moorland Rescuer token's trigger granted by Hofri Ghostforge, returning Moorland Rescuer from exile to your graveyard
8. Resolve the other Moorland Rescuer trigger, returning Moorland Rescuer from your graveyard to the battlefield
9. Repeat

Results

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