Breath of Fury + Battle Cry Goblin + Goblin Chieftain
Breath of Fury
Battle Cry Goblin
Goblin Chieftain
Infinite combat damageInfinite combat phasesInfinite death triggersInfinite creature ETBInfinite creature LTBInfinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite untap of creatures you control
How it works
Declare Battle Cry Goblin, the creature with Breath of Fury attached, and any number of other creatures as attackers.
Battle Cry Goblin triggers, creating a 1/1 Goblin creature token that is tapped and attacking.
Deal combat damage using the creature that has Breath of Fury attached.
Breath of Fury triggers, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to the Goblin token, then causing you to untap all creatures you control and to get an additional combat phase after this one.