There are multiple Bonus Credit classes at CPWS. They are Dragons: A History, Beast Hunting, Stargazing/Astronomy, Ancient Runes, Muggle Studies, Divination, Enchantments, and Dragon Care (only to be attempted by very prepared and smart students!).
These classes are not required, but will give a student better grades.
The professors are:
Enchantments: Professor Splash
Dragons: A History-Professor Maestra
Beast Hunting- Still looking for one to hire!
Stargazing/Astronomy- Still looking for one to hire!
Dragon Care- Still looking for one to hire!
Ancient Runes- Professor Nugget
Muggle Studies- Professor Ginny
Divination- Professor Ginny