{aurelia, the war leader}+ {felhide spiritbinder}
felhide has inspire when untaped it pay {1}{R} copy a creature it is an enchantment in addision to its other types and it has haste
as long as you have the mana.
Aurelia's already 6, so mana's no problem, but, I believe since the creature is a copy of Aurelia it wouldn't keep adding combat phases because its when Aurelia attacks the first time each turn. But I might be wrong.
Isn't Aurelia legendary though?
Yep. That's why you sack her. You get to keep the copy, which is a new creature, and start your additional attack phase.
You will need two creatures like {Sylvan Caryatid} to untap for endless mana. Your lands don't untap with the new angel.
just add {Liege of the Tangle} and make all your lands creatures