Angel of Indemnity, Umbral Collar Zealot, and Felidar Guardian

Prerequisites

• Angel of Indemnity on the battlefield
• Umbral Collar Zealot on the battlefield
• Felidar Guardian in hand

Steps

1. Cast Felidar Guardian by paying its mana cost
2. When Felidar Guardian enters the battlefield, it triggers, targeting Angel of Indemnity
3. Holding priority, activate Umbral Collar Zealot by sacrificing Felidar Guardian
4. Resolve the Felidar Guardian ability, blinking Angel of Indemnity
5. When Angel of Indemnity enters the battlefield, it triggers, returning Felidar Guardian from your graveyard to the battlefield
6. Repeat from step 2

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite surveil 1