FFIV's Boss's Theme, Dreadful Fight (the Fiends theme), and Zeromus's.
FFV's Clash on the Grand Bridge (Battle against Gilgamesh).
FFVI's Fierce Battle (Atma Weapon) and Dancing Mad.
FFVII's Boss's Theme.
Edit: Oh, and FFVIII's The Man with the Machine Gun (Battle music with Laguna).
