In the world the dolls live in, their music taste would include genres like metal, punk, hardcore, industrial, goth, grindcore, etc. You can also dye their hair and give them tattoos. They'd also like to do things like hang out at bars, go to concerts, and meet up with other metalheads, goths, and punks. Their interest range from different movies (like horror and exploitation), TV shows, comics, cartoons, anime, manga, literature, and art.
There could even be a cartoon adaptation for it.