I haven’t read anything by her but I see that she wrote Howl’s Moving Castle, and mostly wrote fantasy. Thank you for mentioning this. I’m definitely more inclined to read something by her now.
V. C. Andrews, known for the ‘Flowers In The Attic’ series, also wrote novels featuring cousin/cousin canon relationships. Some person on reddit told me this. People might already know that, but I didn’t know… 🙂