How many Gods are there in the Christian religion?
Ask a Christian to explain the Trinity sometime when you want a good laugh. To Christians, there is One True God, who is in fact three Gods. There is God the Father who is the Old Testament Jewish God, Yahweh. There is God the Son, Jesus, born of a woman and ascended into Heaven. And then there is the amorphous Holy Spirit. Three completely separate entities with three very different personalities. They pray to them as separate individuals. Sounds like three gods, yeah? Not very monotheistic of them.
Christians explain this in an abstruse, labyrinthine concept call The Trinity. Basically, the three gods are one god, the one god is three gods, and if you don't understand that you are an ignorant twit who will burn in Hell.
The Mother Goddess
Many Christian sects worship the Virgin Mary, the mother of Jesus. There are icons and statues to her. She is prayed to regularly. She appears to people (sometimes as a toasted cheese sandwich) and preforms the occasional miracle. The whole goddess gig.
Angels and Demons
Angels are immortals akin to the servant gods of the Sumerian religion, the igigi gods. According to Sumerian legend, mankind was created because the igigi gods were sick and tired of doing all the work for the greater gods. Mankind were made to be servants to the servants. The concept of rebellious servant gods (fallen angels) goes back to those same Sumerian legends.
There are over 10,000 demigods, called saints. They are prayed to like gods, perform miracles like gods, are worshiped like gods, yet were once human. Part man, part god - the definition of demigods.
So, according to the Christian faith, Heaven is crawling with gods, semi-gods, and demigods. The pantheon of the Christian religion has many more gods than any of the classical polytheistic religions. Valhalla or Olympus would need annexes and high-rise apartments to house all the deities in the Christian Heaven.