While it is impossible to predict what the Gorosei's DFs actually are, I feel like we could possibly speculate on Oda's inspiration for these DFs based off their silhouettes. We can be fairly sure they are mythical zoans, as the Gorosei should easily have access to such powers, and there is absolutely zero reason for Oda to silhouette them if they weren't mythical. However, the issue is that Oda has created original mythical zoans, as is the case with the Nika fruit, where Nika is a concept that doesn't exist in the real world. Hence it is impossible to fully predict what these fruits are, as Oda can literally make up whatever he chooses.
Yet, I think it is possible that even if some or all of these mythical zoans are original, they could be inspired by real world myths. So this is just my guess on what the possible inspirations could be.
Starting from the right, I think that the tusk gorosei's powers will either be or be heavily inspired by the hindu god ganesha, who has an elephant's head. However its ears and tusk seem more reminiscent of a mammoth than of a normal elephant. Hence I think its very possible that this zoan could be an original zoan inspired by ganesha, but whereas Ganesha had the head of an elephant, this god will have the head of a mammoth.
I think that its possible that the tusk gorosei is the God of the Earth, possibly a reference to the myth of elephants holding up the earth.
I think that the bird-like Gorosei will actually be a feathered serpent, inspired by the feathered serpent gods of native american mythology(Quetzalcoatl, Kulkulkan, etc.) My guess is that he will be the god of the forests. I think it makes sense for him to be a feathered serpent, as his wings don't seem to be particularly large.
For the Sword Gorosei, given his human like appearance and the fact that the Gorosei weilds a katana, I think his zoan will be heavily inspired by a shinto god. Specifically Susanoo-no-mikoto.
This god is typically depicted as a swordsman, which would fit the sword gorosei's theme. He is also associated with storms, hence I think this Zoan could be the God of the Rain.
I think the two on the left are probably the weaker Gorosei. They might not necessarily have original zoans, or even zoans at all. I think the one with the open mouth could be a logia or something. With that one, its appearance is so indistinctive, its really hard to predict anything.
For Saturn tho, who's DF appears to make him some bull-like creature, I think its very possible that this Zoan either is or is inspired by the golden calf from the Bible. Saturn kinda looks jewish in his appearance. Specifically his hat, which is remniscent of a kippah, and his hairstyle, which is reminiscent of payot.
If you don't know, there's a scene in exodus where all the jews worship a golden calf statue. I think this could be what Saturn is. Alternatively, I think he could also be Moloch.
Moloch is a canaanite god mentioned in the bible. The story goes that apparently pagans burned children in sacrifice to him. I think these are probably the things Oda is using as inspiration for Saturn's powers. His DF will give him a body made of metal and possibly fire powers as well.
Anyways, that's the theory.
