I have a lot of aroace headcanons but one I haven't seen anyone else have is Howl from Howl's Moving Castle (the book as I've never seen the film).
In the book he has relationships with lots of women but says he cannot love any of them (and believes he is broken) so I read him as a aromantic hetrosexual.
He thinks it is because he literally has no heart but he seems to still love his family so...
At the end he apparently has romantic attraction to Sophie so maybe demiromantic. Though there relationship isn't unambigously romantic so I'd like to think that they were in a platonic partnership. I'd also headcanoned Sophie as ace and maybe aro/arospec so I was disappointed by the sequal (they are married and have a child). The book ended up amatonormative when it had been about friendship and family relationships primarily.