I'm not sure I should ask what kind. We tend to use music, maybe a TV show if we're trying to focus at the morgue. Well, Ravi and I did.
They work a little differently in my world. So long as you get brains at least once a month, you stay coherent. If you don't and you end up going full on zombie mode and starving, it is, currently, impossible to come back from. I try not to let that happen, thus working in a morgue. It's gross, but useful. I work in the sheriff's morgue, which means these people died under suspicious circumstances. My kind of zombie picks up traits and has visions from the brains we eat. It's useful for helping solve their deaths.