Monstrousness levels may vary, but Alaya Dawn Johnson's second Spirit Binders book features a queer equilateral-triangle relationship between a man and two women. One of the women is a magic-userwho eventually becomes entangled with Death in some kind of bargain (that . . . I'm still not entirely clear on, but involves immortality and chopping off her arm) and become the dangerous witch-antagonist of the series who is considered pretty monstrous by the majority of the population.

I don't know Libba Bray's Victorian schoolgirls trilogy - I read the first book, but it was a long time ago - but from what I understand there's a lesbian relationship, and one of the girls involved dies and becomes a 'corrupted spirit' (thus says Wikipedia.)

If I remember correctly, Pamela Dean's Tam Lin features at the very least rumors of vague lesbianity around all of the fairy-court-affiliated professors, and Janet occasionally gets warned about this by people attempting to be helpful.

And if anime counts, of course there's Anthy Himemiya, prominent anime lesbian and shapechanging witch.