Breath of Fury attached to another creature you control).
Easy Prerequisites
There are creature cards in your library.
Notable Prerequisites
An opponent cannot block creatures you control.
Steps
Declare
Raph & Mikey and the creature with
Breath of Fury attached as attackers.
Raph & Mikey triggers, revealing a creature card from your library and putting it onto the battlefield 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 creature put onto the battlefield in step 2, and then causing you to untap all creatures you control and to get an additional combat phase after this one.
Repeat each combat phase until you have no creatures left in your library.
Notes
The number of combat phases you can get will be equal to the number of creature you control (excluding those listed in this combo) plus the number of creatures in your library plus 1.
Results
Near-infinite ETB.
Near-infinite LTB.
Near-infinite combat damage.
Near-infinite combat phases.
Near-infinite death triggers.
Near-infinite sacrifice triggers.
Near-infinite mana creatures you control can produce.