If you look for something like March of Cambreadth, then this is worth hearing. Turisas might by for you as well. It's more metal, but a similar attitude is maintaned. Apart form that, scottish bagpipes rock should work - it even comes in a hilarious/crazy variety.
If you actually consider making a training montage during your campaign, then Scarface had just the tune for it. Or go with a well-known classic.
If I ever introduce Fae in my games, they will be supported by Elfman's music: 1, 2, 3. Other eerie themes to consider: 1, 2, 3.
Possible crazy music (apart from a suitable kind for treatment): 1, 2, 3, 4
This has a nice buildup at the beginning.
This is a fairly good march, but it would require a whole hoard of bards instead of a single one.
Kilar's music from Dracula might be an interesting choice as well.
If you want to confuse your players, then the villain in question might have a taste for more upbeat music: 1, 2.