There are some fanfiction communities on Reddit too. Maybe post a request there, saying you're looking for a fanfiction where Hermione is tortured in the context of her relationship with Ron. But be aware that not all content there might be suitable or well - written.
Another option is Archive of Our Own (AO3). It has a very extensive library of fanfictions. You can use the search function and filter by the relevant tags like 'Hermione torture' and 'Ron and Hermione relationship' to narrow down your search.
I'm not a big fan of such dark fanfictions, but you could try looking on fanfiction.net. They have a large collection of Harry Potter fanfictions, and you might be able to find one with that plot there.
Perhaps it's about creating a sense of drama and high - stakes. Torture is a very extreme and emotional situation. By putting Hermione in this position, the author can draw out strong emotions from the readers. It could also be related to character development. Hermione is often seen as a strong and intelligent character. Through torture, the author might want to show her vulnerability and how she overcomes it, while also showing Ron's role in that process.
There's a fanfic called 'Hermione's Heroism'. It details how Hermione risks everything to save Ron when he's been poisoned. The author does a wonderful job of showing Hermione's determination and her love for Ron through her actions. It also has a really interesting sub - plot about Hermione exploring some ancient magic to find the cure.
One great fanfiction could be where Ron and Hermione face new challenges in the post - Deathly Hallows world that were not explored in the original. For example, they might have to deal with some dark magic remnants that are affecting the wizarding world's new peace. It could show their relationship growing even stronger as they work together to solve these problems.
One great fanfiction could be 'The Hand - Held Bond' where Ron and Hermione's hand - holding is not just a physical act but a symbol of their growing emotional connection. It beautifully portrays how their relationship evolves through this simple gesture.
I recall one fanfiction where the 'Mudblood' concept was explored in a very different way. Hermione was trying to find a way to remove the stigma associated with it. Ron was by her side throughout this journey. And Harry's scar was somehow a key to unlocking an old magic that could potentially change the wizarding world's view on blood purity. It was a really interesting take on the characters and these concepts, and it showed how strong Ron and Hermione's relationship could be in the face of such complex issues.
There's a fanfiction I read where Ron and Hermione are getting married and Harry and Ginny are helping with the preparations. It has some really sweet moments like when Harry gives Ron some advice on married life based on his own experiences with Ginny. And there are also some funny parts where Ginny teases Hermione about her wedding jitters.
One great Hermione and Ron Weasley pregnant fanfiction is 'The Next Chapter' which beautifully portrays their journey into parenthood. It shows how they deal with the excitement and nervousness. Another is 'Family Beginnings' where the author focuses on Hermione's pregnancy cravings and Ron's attempts to satisfy them in the most hilarious ways.
I really like 'Soulmates Beyond the Battle'. In this fanfic, it focuses on how Ron and Hermione's soulmate connection was actually there all along during the war. It gives a different perspective on their relationship during those difficult times, and the way they support each other as soulmates in the face of danger is really heart - warming.
One great Ron and Hermione Tumblr fanfiction is 'The Unspoken Bond'. It beautifully captures their relationship's growth from friends to something more. The author's writing style is engaging, and the way they portray the characters' emotions is very realistic.
A popular one is 'New Beginnings'. Here, the story focuses on how Hermione copes with Ron's betrayal and how Draco enters her life at that crucial moment. It shows a different side of the Hogwarts world and the characters, with their relationships evolving in unexpected ways.