Hero of the Dunes, Fiend Hunter, and Phyrexian Altar

Prerequisites

• Hero of the Dunes in exile
• Fiend Hunter on the battlefield
• Phyrexian Altar on the battlefield

Steps

1. Activate Phyrexian Altar by sacrificing Fiend Hunter, adding one mana of any color
2. When Fiend Hunter dies, its second ability triggers, returning Hero of the Dunes to the battlefield from exile
3. When Hero of the Dunes enters the battlefield, it triggers, returning Fiend Hunter from your graveyard to the battlefield
4. When Fiend Hunter enters the battlefield, its first ability triggers, exiling Hero of the Dunes
5. Repeat

Results

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