How many mythologies exist in history is a very interesting question but one that is almost impossible to answer. Also, how would you count them? Would each god and goddess be counted individually? Regardless, throughout history, mythologies have existed in virtually every culture and area of the world. The earliest mythologies that we are aware of begin in the Middle East and South Asia with Gilgamesh, The Babylonian Creation Story, Horus, Osiris, Ra and Pharaohs in ancient Egypt.
There are also The Bhagavad Gita, Buddha, One Thousand and One Nights, and more. The Greek Titans and Titanesses came before the Greek and Roman gods and goddesses. There were also Dagda’s Harp and other Celtic myths, Norse myths involving Odin, Thor, hammers, rings and other Norse magic. This covers just Europe and the Middle East. There are also myths in the Americas, Africa, and Asia Pacific regions of the world.
All of the different regions of the world have their own distinct and exclusive mythologies. For example, the Middle East is the home of various religious mythologies such as Christian mythology, islamic mythology, and Jewish mythology. Greek mythology is probably the more famously known of the mythologies in history. The number of mythologies that have existed in history could easily number in the hundreds and push towards the thousands.
It is just the main ones such as Greek mythology and Roman mythology that most people are familiar with. Each one of these mythologies have their own list of gods and customs and then have sub-mythologies under them. This is the case in a lot of areas such as the Polynesian Islands and all throughout Africa. These mythologies play an important part in the history and the culture of many of places all throughout the world. It is in essence one of the identifying features of a lot of places.