In fact Thomas Jefferson had this to say about the so-called Holy Trinity:
"no one sees with greater pleasure than myself the progress of reason in it’s advances towards rational Christianity. when we shall have done away the incomprehensible jargon of the Trinitarian arithmetic, that three are one, and one is three; "
I actually preached on this at the "Unity Sunday" service at Mill Hill Chapel, Leeds (Unity Sunday being the Unitarian response to "Trinity" Sunday).
Trinities in religion aren't that big of a problem in world religions. If breeders want a trinity, then give them a trinity.
Ancient Egyptian Religion - you can easily find Father, Mother, and Child.
There's nothing unreasonable about making this archetype of breeding.
Now, Father, Son, and Holy Spirit isn't a good example of a Trinity. It's difficult to say there is a Feminine Principal in the Christian Trinity. Father, Son, and Holy Spirit are not archetypes: they are spiritual characters in the gospel narrative. If the early Christians wanted to make a Trinity of their literary spiritual characters, it's not that big of a deal.
In Kabbalah, there are Trinities and there are 10+ spheres/manifestations of God and Ain Sof, the unmanifested/Nothingness.
Let me see if I remember:
3 spheres on the left
3 spheres on the right
1 sphere on the bottom
1 partial sphere between Father and Mother
another sphere in the middle of the diagram
2 on the bottom
There are 99 Names of Allah.