Alternative hip hop - opposite of gangsta rap, usually includes socially or politically aware lyrics (also known as alternative rap or Bohemian hip hop)
Beatboxing - Music performed by producing percussive and melodic sounds with the mouth alone, often mimicking instruments, recorded samples and other sounds not typically associated with vocalization.
Bebop - 1940sjazz style with complex improvisation and a fast tempo
Bubblegum pop - sometimes synonymous with pop music, especially that performed by teen idols; can also refer to specific styles of South African or Japanese pop