I was reading a LOTR AU (
No Man's Child by Anoriath, it's unfortunately an unfinished WIP, and sadly seems abandoned since 2007), and I had a hard time figuring out why I liked it so much, when at first glance it has a lot I don't care for: First, it is Aragorn/OFC and I'm pretty much set on Aragorn/Arwen as my OTP by inclination. And I like AUs much less in LOTR than in most other fandoms. Also, it is from the OFC's POV and Aragorn as well as other canon characters appear only occasionally.
Eventually I realized that the whole thing, all 180k words of it, basically caters to my service kink. The premise of the story is that a few years before the ring war in wake of suffering a serious injury Aragorn bows to pressure from the Dunedain to take a wife and produce an heir to secure Isildur's line, but it does not change that Aragorn loves Arwen. We don't get to see his thoughts on this as the POV is exclusively the OFC's, and she doesn't even know Aragorn personally before meeting him for the wedding, as he sent Halbarad to ask for her. So there is no love story at all, though eventually they become fond of each other in a way. She somewhat more of him than he of her, but the distance and ritual courtesy never vanishes.
The story then mostly follows how the OFC dutifully reorganizes his household, and tries to manage politics and feudal obligations among the remnants of the Dunedain with a good amount of vivid detail, because besides wanting an heir, Aragorn asked her help keep his remaining people safe while Sauron's threat grows, yet he is mostly away doing the things he does in canon at this time, i.e. hunting for Gollum, which the reader knows, but the OFC doesn't in any detail. Eventually they are also successful with the reproductive duties, which I found nicely handled, because Aragorn does not really want to have sex with her more than absolutely necessary (he doesn't confide to her about Arwen, but the OFC realizes fairly soon that he is love with someone he couldn't marry), while she is okay with the sex but uncomfortable to press him too boldly, but also feels the pressure that conception needs to happen for his dynasty as well as for her household position, which is all complicated by him being frequently absent.
All of which is fairly bleak from a romance angle, but from a certain kind of service kink perspective it is a delightful wallow, because the OFC acts the whole time in the service to her lord, and while companionship grows between them over time the status difference is never forgotten, and meanwhile Aragorn is seen to act in service to his people even against his own desires, because it is his duty to secure his family line. So that satisfies twice over.
So I'm happy I gave this a try even though from its bare headers it seemed not to fit with my preferences at all. Anyway, if you share that particular kink (and don't mind the unfinished status) you should check this out. Also if you like stories of ordinary folk's everyday life against the backdrop of the build up to the ring war.