Excava, the Risen Past + Solemnity + Breath of Fury
Excava, the Risen Past
Solemnity
Breath of Fury
Infinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite untap of creatures you controlInfinite creature ETBInfinite creature LTBInfinite combat damageInfinite combat phasesInfinite death triggers
How it works
Declare Excava and the creature with Breath of Fury attached as attackers.
Excava triggers, returning up to one creature with haste and mana value 3 or less from your graveyard to the battlefield. It won't enter with a finality counter on it due to Solemnity.
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 a creature with haste and mana value 3 or less, then causing you to untap all creatures you control and to get an additional combat phase after this one.