Havi, the All-Father, Saffi Eriksdotter, and Ashnod's Altar

Prerequisites

• Havi, the All-Father on the battlefield
• Saffi Eriksdotter on the battlefield
• Ashnod's Altar on the battlefield

Steps

1. Activate Saffi by sacrificing it, targeting Havi
2. When Saffi dies, Havi triggers, returning any legendary creature card with mana value 1 or less from your graveyard to the battlefield
3. Resolve the Saffi ability
4. Activate Ashnod's Altar by sacrificing Havi, adding
5. When Havi dies, it and Saffi trigger
6. Resolve the Havi trigger, returning Saffi from your graveyard to the battlefield
7. Resolve the Saffi trigger, returning Havi from your graveyard to the battlefield
8. Repeat

Results

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