Ugh this is so hard...
FF1 Battle theme (a classic)
FF2 Castle Pandemonium
FFIV Theme of Love :3
FFV Battle on the big bridge
FFVI Searching for friends or Edgar's theme
FFVII Battle theme/Let the battles begin FFVIII (too hard to choose ugh) Force your way, The extreme, Maybe I'm a Lion
FFIX Roses of May, Festival of the hunt
FFX A fleeting dream
FFX-2 Farplane abyss
FFXII Esper battle or Rabanastre theme
FFXIII Blinded by light
FF type 0 We have arrived
CC: the soldier way
FF MQ Battle 2