Novels with either plain obsessive love or twisted relationships. Keep in mind that these are all my personal ratings so it may not be the same for you but still, take it as a reference if you're unsure of what to read next. 

Yandere Levels ; 10 - borderline obsessive w/ actual reasons   ▎8 to 9 - definitely obsessive but not too much  ▎5 to 7 - obsessiveness that came out of no where (aka just bcuz fl's nice to ml etc.)

Plot ; 10 - interesting and unique  ▎8 to 9 - decent / common but tolerable  ▎5 to 7 - plain and usual / not so surprising