There might be some out there, but it goes against the canon where they are in love. However, if you're set on it, look for stories where the author decides to take a really different path from the books. They might rewrite the characters' personalities completely so that Harry and Ginny end up hating each other. But I can't really name a specific one off the top of my head.
I'm not really into that concept as in the original series they love each other. But you could try searching on some big fanfiction platforms like FanFiction.net or Archive of Our Own. Maybe use the tags related to Harry Potter, Harry, Ginny and 'hate relationship' to find what you want.
One possible plotline could be that Ginny is jealous of Harry's fame and starts to resent him for always being in the spotlight. Another could be that Harry mistakes Ginny's actions for something malicious and they start to dislike each other from there. Maybe Ginny blames Harry for something that happened to her family during the war, even if it wasn't really his fault.
Yes, there are some. You can check on fanfiction websites like FanFiction.net. Some authors explore this rather unorthodox relationship concept in their works, often creating interesting plot twists and character developments.
One reason could be jealousy. Maybe Hermione is jealous of Harry's fame and Harry is jealous of Hermione's intelligence. Another reason might be conflicting views on how to deal with Voldemort. Hermione might advocate for a more academic, research - based approach while Harry just wants to go and fight.
One popular 'Harry and Ginny secretly married fanfiction' is 'The Secret Bond'. It delves into how they managed to keep their marriage a secret from their friends and family initially. It has some really sweet moments of them navigating their new relationship status while still being part of the wizarding world.
One popular 'Harry and Ginny Slytherin fanfiction' is 'A Different Sort of Magic'. It explores what would happen if Ginny was sorted into Slytherin. The story delves into how she and Harry would interact in this alternate scenario. It shows Ginny using her Slytherin traits, like cunning and resourcefulness, to help Harry in their fight against the Dark forces. The character development is really interesting as they both have to navigate a relationship that is different from the canon due to Ginny's house change.
One possible reason could be a misunderstanding. Maybe Ginny overheard Harry saying something that she misinterpreted, leading her to want to avoid him. For example, if Harry was talking about his future plans and Ginny thought he was excluding her from them without really understanding his full intention.
Well, there's this fanfiction called 'Love's First Kiss'. It shows a really sweet and tender moment between Harry and Ginny when they kiss. It also delves into their emotions and how their relationship has developed over time. The description of the setting and their feelings makes it a great read.
I'm not sure about a specific one that stands out above all others. But generally, in such fanfictions, they often get to travel the world, discover hidden magical places that normal wizards could never reach in a normal lifespan. They might also use their immortality to protect the wizarding world from threats that surface over centuries. You can search on fanfiction platforms using keywords like 'Harry and Ginny are immortal' to find some interesting ones.
There's also 'Ginny's Heart'. In this fanfiction, it delves deep into Ginny's perspective when she's in love with Harry. It shows her internal struggles, her hopes, and her dreams related to their relationship. The writing style is quite vivid and makes the story very immersive.
A really good one is 'Harry and Daphne: An Unexpected Love'. This story focuses on how Harry, who has been through so much, finds solace and love in Daphne. Daphne, on the other hand, is drawn to Harry's courage and kind heart. The story is filled with sweet moments between them, and the author also weaves in some interesting sub - plots that make it a very enjoyable read.