Think of superfatting as something you do, rather than as a type of oil or fat.
When you add more oil/fat than your lye solution can react with, it is known as superfatting. It is basically unsaponified fat in your finished soap.
So really, you can superfat with any oil/butter/fat.... but depending on your recipe, your superfat percentage and whether you use the Cold or Hot Process method, you may end up with different results!