In some darker fanfics, Sirius might be faking ignoring Harry as part of a plan to protect him from a greater threat. He thinks that by distancing himself from Harry, he can keep Harry out of danger. But of course, Harry doesn't understand this at first and is deeply hurt.
One great 'Sirius helps Harry' fanfic is 'The Bond Beyond Blood'. In this fic, Sirius helps Harry master some advanced magic that Dumbledore didn't have time to teach him. It's really interesting as it shows a different side of their relationship, more like a father - son bond in the world of magic.
There's a fanfic called 'Padfoot and Moony's Little Cub'. In this one, Sirius and Remus raise Harry in a cottage hidden from the wizarding world. Harry grows up learning about his parents from the two men who knew them best. It has some really heartwarming scenes where they celebrate Harry's birthdays and teach him about the Marauders' adventures.
One great 'Harry x Sirius Comfort' fanfic is 'A Shoulder to Lean On'. It beautifully portrays Sirius being there for Harry during a tough time at Hogwarts. The author does an amazing job of showing their bond through simple yet powerful interactions.
One thing to keep in mind when looking for such a fanfic is that it might be a bit hard to find as it's a rather specific and dark concept. Some fanfic writers might be hesitant to write about such extreme torture scenarios. You could also check fanfic communities or forums dedicated to Harry Potter. Post a request there asking if anyone knows of a fanfic with this plot. Maybe someone has come across it or has even written one themselves.
One popular fanfic with this theme is 'Time's Threads'. In it, Harry and Ginny use a time - turning device to go back and save Sirius. The story is really engaging as it shows their struggle to fit into the past timeline without disrupting too much. They face challenges like dealing with the younger versions of their friends and family.
One great fanfic could be 'The Bond Between Them'. In this fic, Sirius's encounter with baby Harry is depicted with a lot of emotion. It shows how Sirius immediately feels a deep connection to the little boy, and there are some really heart - warming scenes of Sirius protecting Harry from potential threats even at that young age.
There is a fanfic where James Sirius Potter discovers a hidden mystery in Hogwarts. In this story, he teams up with some new friends. The author does a wonderful job of creating a believable world and the relationships between the characters are really well - written. It's a great read if you want to explore more about this character.
There's also 'Sirius's Oath'. It shows Sirius making an unbreakable vow, in a way, to always protect Harry. It delves into their relationship, with Sirius teaching Harry things he never learned at Hogwarts, all while shielding him from the dark forces that are after him. It's really interesting as it also shows how Sirius's protectiveness affects Harry's growth as a wizard.
I really like 'A Ray of Hope in the Darkness'. In this fanfic, Sirius is depressed after the events that have befallen him. Remus is portrayed as a very patient and loving character. He slowly helps Sirius heal by being there for him, and the story is full of emotional moments that will make you feel for both characters.
One great 'Dark Harry and Sirius' fanfiction is 'The Unseen Bond'. It explores a darker side of Harry's magic while maintaining a strong connection with Sirius. The story is full of twists and turns that keep you on the edge of your seat.