There is absolutely an absurd amount of Kit Kat flavors out there. Taken straight from the most reliable source of information, Wikipedia, "There have been more than 300 limited-edition seasonal and regional flavors of Kit Kat chocolate bars produced in Japan since 2000."
(The actual source is from a CNN article from 2012, however there they only mention over 200 special edition flavors)
Whatever the case, the article is almost a decade old so the actual numbers might be significantly higher.