Breath of Fury attached to another creature you control that does not have summoning sickness.
An opponent cannot block creatures you control.
Steps
At the beginning of your combat phase, Boundary Lands Ranger triggers, causing you to rummage.
The Locust God triggers, creating a 1/1 Insect creature token with flying and haste.
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 Insect token, then causing you to untap all creatures you control and to get an additional combat phase after this one.