Dowsing, horoscopes, homoeopathy, other than the well known placebo effect including which doctors, laying of hands, which craft, possession by spirits, demons etc, out of body experiences, spiritualism, ghosts, religions any religion, vampires, treading on the cracks in the pavement, most superstitions in general.
It's all good stuff for the more gullible of us out there, I'm sure there's plenty more if you look hard enough.
Regards to all ippy