Final Fantasy Mystic Quest...

[Dice]

...battle & boss theme!!

For an SNES and for over ten years, I always thought these themes were pretty damn intense. The game might not have been extraordinary, but these were always a joy to listen to. =p

[Chickenwarlord]

This will probably have something along those lines.

http://ffmq.olremix.org/

Be warned, OLRemixes are totally different qualitatively than OCRemixes.

[Rexy ⚖️]

Ashane covered the battle theme if you want that. It was in the Dwelling of Duels May/June 2004 Free Month.