Mazzy, Truesword Paladin, Ashnod's Altar, Gift of Immortality, and Brazen Freebooter

Prerequisites

• Mazzy, Truesword Paladin on the battlefield
• Ashnod's Altar on the battlefield
• Gift of Immortality on the battlefield
• Brazen Freebooter on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Brazen Freebooter, adding
2. When Brazen Freebooter dies, Mazzy's second ability and Gift of Immortality trigger
3. Resolve the Mazzy trigger, exiling Gift of Immortality with the ability to cast it until end of your next turn
4. Resolve the Gift of Immortality trigger, returning Brazen Freebooter from your graveyard to the battlefield
5. When Brazen Freebooter enters, it triggers, creating a Treasure token
6. Activate the Treasure by tapping and sacrificing it, adding
7. Cast Gift of Immortality from exile by paying , attaching it to Brazen Freebooter
8. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite sacrifice triggers
• Infinite storm count