Here's my personal suggestions for Boss Theme Songs, I'm currently using theme on my own FF2 Server
I'll Post here all my custom choices for FF2 Bosses (for existing bosses, or for some of my bosses)
The Turkish March - Ulytau : Octavia & Brian Duo Theme - Freak Fortress 2
Lion - Eugene McGuinness : Big Brian's Theme Song - Freak Fortress 2
Nightmare - Love Automatic (FF2 Loop Edit) : SCP-173 Theme Song - Freak Fortress 2
Weapon - M4Sonic : Vinyl Scratch Theme Song V2 - Freak Fortress 2
Fort Boyard Theme Song : Saxton Hale's Theme Song - Freak Fortress 2
Shuriken School Opening Theme Song (FF2 Loop Edit): Ninja Spy - Freak Fortress 2
FF2 Bosses (from this Soundtrack List) i have made:
_Big Brian The Banned from Equestria
_SCP-173
_Vinyl Scratch V2 (Re-scripted, Voiced by Nowacking)