Sister Hospitaller, Ashnod's Altar, and Fiend Hunter

Prerequisites

• Sister Hospitaller in hand
• Ashnod's Altar on the battlefield
• Fiend Hunter in the graveyard
• available

Steps

1. Cast Sister Hospitaller by paying
2. When Sister Hospitaller enters, it triggers, returning Fiend Hunter from your graveyard to the battlefield and causing you to gain life equal to its mana value
3. When Fiend Hunter enters, it triggers, exiling Sister Hospitaller
4. Activate Ashnod's Altar by sacrificing Fiend Hunter
5. When Fiend Hunter dies, it triggers, returning Sister Hospitaller from exile to the battlefield
6. Repeat from step 2

Results

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