This is a very interesting Map showing all the Writing Systems of the World.

The four main one are Latin, Arabic, Chinese and Cyrillic

Than we are having many others like Georgian, Armenian, Greek, Hebrew, Tifinagh, Amharic, Thaana, Mongolian, Japonese, Korean, Yi, Burmese, Lao, Thai, Khmer, Burginese, Sinhala, Tibetan, Oriya, Gurmikhi, Kannada, Devanagari, Telugu, Gujarati, Malayalam, Bengal, Tami, Cherokee, Inuktitut, …