Breath of Fury, and Legion Warboss

Prerequisites

• Breath of Fury on the battlefield
• Legion Warboss on the battlefield
• Breath of Fury attached to any creature that can attack this turn
• An opponent is unable to block and kill creatures you control

Steps

1. At the beginning of combat phase, Legion Warboss triggers, creating a 1/1 Goblin creature token with haste
2. Deal combat damage using the creature with Breath of Fury attached
3. Breath of Fury triggers, causing you to sacrifice the creature it is attached to, attach Breath of Fury to the Goblin token, then untap all creatures you control and get an additional combat phase after this one
4. Repeat each combat phase

Results

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