Felidar Guardian, Conspiracy, Valkyrie's Call, and Yahenni, Undying Partisan

Prerequisites

• Felidar Guardian on the battlefield
• Conspiracy on the battlefield
• Valkyrie's Call on the battlefield
• Yahenni, Undying Partisan on the battlefield

Steps

1. Activate Yahenni by sacrificing Felidar Guardian
2. When Felidar Guardian dies, Valkyrie's Call triggers, returning Felidar Guardian from your graveyard to the battlefield as an Angel
3. When Felidar Guardian enters the battlefield, it triggers, blinking Conspiracy
4. Choose any creature type except "Angel" as Conspiracy enters the battlefield
5. Resolve the Yahenni ability
6. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers