I created MIDIs (sometimes convert to mp3 by Cubase) for Doom and another games in 10 music styles:
1) Hard Rock;
2) Heavy Metal;
3) Post-punk;
4) Classic;
5) Rap;
6) Synth Pop
7) Jazz;
8) New Age;
9) Anime music;
10) Gothic.
Because I love a variety in music.