Yenna, Redtooth Regent, Agatha's Soul Cauldron, Ashnod's Altar, and Sky Hussar

Prerequisites

• Yenna, Redtooth Regent on the battlefield
• Agatha's Soul Cauldron on the battlefield
• Ashnod's Altar on the battlefield
• Sky Hussar on the battlefield
• plus enough mana to activate the Licid's ability
• available

Steps

1. Activate Sky Hussar using the Licid's ability by paying its activation cost, attaching Sky Hussar to Yenna and causing Sky Hussar to become an Aura
2. Activate Yenna by paying and tapping it, creating a token copy of Sky Hussar
3. When the Sky Hussar token enters, it triggers, untapping all creatures you control Activate Ashnod's Altar by sacrificing the Sky Hussar token, adding
4. Repeat from step 2

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite untap of creatures you control
• Infinite mana creatures you control can produce