Atheism - an absence of belief in the existence of deities. A rejection of the belief that any deities exist or that there are no deities. Atheism views creation as merely the product of time, energy, and chance - the Big Bang.
Monotheism - belief in only one God - there are no other gods. "Monotheism asserts that there is only one divine nature or essence—nothing else exists that is like God or comparable to God." The doctrine of monotheism is concerned with the otherness of God while the central aspect of monotheism is the belief that all existence is dependent on God and owes existence to only Him. We see this concept in Hebrews 11:3 - the universe was not made out of things that are visible. It's arguable however that this can only be for the ultimate supremeness of God since He did not create from pre-existing matter, rather, He spoke everything into existence. "the worlds were framed by the word of God". (Gen 1:1–2:3; Isa 44:24; 45:12)
Polytheism - belief in and worship of many gods
Henotheism - belief in and worship of one primary God while acknowledging the existence of other gods
Pantheism - the belief that God is everything and everything is God - God is the Universe.
Panentheism - God is both transcendent and immanent, God is beyond the universe but also present within it
Dualism - belief in two opposing forces, such as good and evil, light and dark, or God and the Satan
John Anthony Dunne, “Monotheism,” ed. John D. Barry et al., The Lexham Bible Dictionary (Bellingham, WA: Lexham Press, 2016).
So then...who's God is really God?