I recommend watching
The Skeleton Key to get an idea of what voodoo is capable of, though they call it hoodoo in the film. I don't want to get into a debate about which is correct or applicable for this situation.
Suffice to say, the ritual magic will probably cover a lot of things under entropy and ectomancy. The good side would be protection from entropy curses and evil spirits, either on an individual basis or strengthening thresholds, and possibly some potions that help protect/heal from mental assults. The bad stuff would be bad luck curses, voo doo dolls, binding evil spirits into animals (like crocodiles), and maybe even switching bodies.