I don’t think Norse mythology ever explicity states what it is that Sigyn rules over, as a goddess. It is, of course, totally possible that I am mistaken - I am no authority, by any means. I just don’t remember having ever seen that distinction made in anything I’ve read thus far. The only similiar thing I can think of is that her name roughly means “victorious” or the kenning “Incantation Fetter” which, in all honesty, I can’t remember the origin of (I’m sure that when I discovered this bit of info it was accompanied by a source, but for the life of me I don’t know what that might have been or if it was, in fact, present).
As such, it’s very interesting to me to see what people associate her as being the goddess of (that was a weird sentence). I’ve seen goddess of fidelity, goddess of constancy, and a couple other things along those lines. From what I can infer these are all based on her relationship to Loki, specifically to the role she plays as far as the myth of his binding goes.
Anyhoo…this brought on by some Avanger’s-related art I saw and found interesting. But while I’m at it, I thought I would include a piece from Gangleri’s Grove, 73 Adorations to Sigyn.