We have two horse queens in South Peloria/Dragon Pass. Both occupy the same ecosystem but both have very different cultic functions.
The first is of course the Feathered Horse Queen. She’s an incarnation of Ernalda, ruler of the Pure Horse People of the Grazelands, protector of the farming peoples of the Grazelands, and is the subject of fanatical loyalty from the Humakt cult.
The second is the Queen of Filichet, the provincial ruler of Holay. She’s of Sairdite origin, likely a combination of things merged together during the Second Age, but also with ties to the ancient Hyalorings, the long-removed ancestors of the Pure Horse People. These traditions have been separated for nearly a thousand years. And yet they reach to similar archetypes and places in the Hero Plane – the horse-loving goddess who grants the right to rule the land.
Interestingly the horse loving goddess does not receive cult directly but almost always as part of another larger cult.