Earlier today, I answered a question over on Quora which asked whether Pagans believed in more than one pantheon. I would like to duplicate part of that answer here.
The other thing that I will note is that in my opinion, “pantheons” are mostly a cultural construct. They’re the result of a bunch of cults to different gods existing in close proximity and their various members intermingling. In this sense the “Greek pantheon” is simply a collection of the various deities that the various people living in Greece (or more properly, the Greek city-states) worshiped. Eventually, people started trying to figure out how these various deities related to each other, and the myths explaining those relationships emerged.
I think that as the modern Pagan movement gains traction and maturity, we might see new pantheons emerge. That is, rather than merely talking about what culture a given deity originated, we will start inventing new stories to explain their relationships to the various other deities they find themselves co-existing with today.
I found this idea both fascinating and appealing. As I mentioned in my answer, I believe that pantheons are the result of different cults/religious groups that worship different deities living in proximity of one another. So why do we still think about ancient pantheons rather than the pantheons that might be forming in our own communities by virtues of which deities we each worship while living together?
And what about the more eclectic Pagans among us who tend to worship different deities who stem from different cultures? Does it not make sense to think of this disparate group as forming a sort of pantheon today? Perhaps even new myths about how Aphrodite and The Morrigan relate to one another and share a follower in common. In many ways,
I imagine the more strict reconstructionists are practically howling in rage at this idea. But some of us are much more innovative and are not as interested in maintaining some weird (and often illusory) sense of historicity. instead, we cherish the (again, sometimes illusory) historical roots, but take them in new directions. And this is okay.
For those of us who are so innovative, I think developing new pantheons and even myths explaining the wide variety of deities is a rational and natural development of our pagan traditions as they grow and mature. Such a thing might even be necessary for that growth and maturity. After all, it might help add some level of cohesion to the often scattered and disparate gods whose names get bandied about in an almost random-seeming manner.