Hinduism: A major polytheistic religion originating from ancient India with many gods including Brahma, Vishnu, Shiva, etc.
Ancient Egyptian Religion: Another prominent example of polytheism focused on various deities such as Ra (sun god), Isis (goddess of magic), Osiris (god of the afterlife), etc.
Mayan Religion: The religious beliefs practiced by the Mayan civilization in Mesoamerica which involved worshiping multiple gods related to nature, agriculture, warfare, etc.