Polytheism is the worldview that many finite gods exist in the world. There are differing versions of polytheism. In some forms, all the gods are more or less equal. Each has a personal sphere or domain. In others, the gods form a hierarchy.
Henotheism has a chief god, such as Zeus. In some forms, such as the Greek and Roman pantheons, the number of gods is limited.
Mormonism supports an indefinite number of gods. Some forms of polytheism stand alone, unconnected with any other worldview.
In Hinduism, however, polytheism and pantheism go hand-in-hand with one impersonal Brahman and 330 million-plus personal manifestations of the one impersonal ultimate Reality.
Problems With Polytheism:
If God is infinite, there can't be more than one infinite Being. To distinguish one being from another, they must differ in some way. If they differ in some way, then one lacks something that the other one has. If one being lacks something that the other one has, then the lacking being is not infinite because an infinite being by definition, lacks nothing. So there can only be one infinite Being.