I have a few:
- Chosen ones, fate, destiny, &c. When you get down to it, a story with these themes is one where a single person or handful of people is ontologically, cosmically better and more important than everyone else. It's eerily similar to that right-wing meme about how "most people are just NPCs" (though I disliked the trope before that meme ever took off).
- Way too much importance being given to bloodlines by the narrative (note, this is different from them being given importance by characters or societies in the story).
- All of the good characters are handsome and beautiful, while all of the evil characters are ugly and disfigured (with the possible exception of a femme fatale or two).
- Races that are inherently, unchangeably evil down to the last individual regardless of upbringing, society, or material circumstances.
I have vague memories as a teenager reading The Night's Dawn books under the desk at school, getting really embarrassed by the multi-page hardcore sex scenes and the protagonist being, uh, a pretty bad person.
There's just something about Doorstop Sci-fi books that seem to lead their writers into trying their hand at fancy space smut.
It contrasted to Melanie Rawn's Dragon Prince series, which I read around the same time, where (IIRC) it's either wholesome romance or very obviously intended as something deeply unhealthy... although there was a lot of that!