Remember Voracidous, Terramorphous, or Haderax?
Here are their themes for you to enjoy!
Stealth: https://www.youtube.com/watch?v=53CAzh_qCGE
Control: https://www.youtube.com/watch?v=LiMOkq1RLac
Buildup: https://www.youtube.com/watch?v=07zoRdoE-Tg
Assault: https://www.youtube.com/watch?v=RV33Fa0RV6Q&t=2s
Alt Assault: https://www.youtube.com/watch?v=zR4DNVm7yUA

You'll need Beardlib, SuperBLT, and CustomOst
After you install both of those open the mods folder and drop CustomOst in there
Drop the BL2RaidBoss folder in the CustomOstTracks folder

1. C:\Program Files (x86)\Steam\steamapps\common\PAYDAY 2\
2. C:\Program Files (x86)\Steam\steamapps\common\PAYDAY 2\mods
3. C:\Program Files (x86)\Steam\steamapps\common\PAYDAY 2\mods\CustomOSTTracks