Aurelia, the Warleader + Rionya, Fire Dancer

Aurelia, the Warleader
Rionya, Fire Dancer

Requires
All permanents on the battlefield. An opponent is unable to block and kill creatures you control.
Steps
  1. At the beginning of your combat phase, Rionya triggers, creating at least one token copy of Aurelia
  2. Put all but one Aurelia into your graveyard due to the legend rule, ensuring the remaining Aurelia has not attacked this turn
  3. Declare the remaining Aurelia as an attacker
  4. Aurelia triggers, untapping all creatures you control and causing you to get an additional combat phase after this one
  5. Repeat each combat phase
Results
Infinite combat phases. Infinite ETB. Infinite LTB. Infinite death triggers. Infinite untap of creatures you control.