There's a zone name generator for SRB2. However, it was made in 2008, and only ever uploaded to a free file host. In other words, the link is dead.
Luckily for you, I still have it, so I re-uploaded it here.
Another good idea might be to find a free (not copyright protected) piece of music that you enjoy or better to create a midi file by yourself that is meant to be played as backgroundmusic and to build what comes to your mind when you listen to this song.
This, so much. I know it's not for everyone, but music is my main source of inspiration. Every single player level I've ever conceived has been the result of me listening to music. I only wish I could make levels as fast as I could think of them...