Using "B":
* Bad and Boisterous
* Bad Business
* Bad Break
* Bad Boy
* Bad Behavior
Using other letters:
* Dangerously Deadly
* Frightfully Fearsome
* Ghastly Gloom
* Sinfully Sickening
* Terribly Troublesome
You can also combine these to create more complex alliterations, like "Bad Business Deadly Danger."