Yes, there are quite a few. Some explore the unique bond between Harry and Remus in this 'cub' relationship. They often delve into how Remus might take on a more paternal role towards Harry, protecting him and teaching him things he didn't learn from the Dursleys.
The common themes can be quite diverse. For instance, there's the theme of growth. Harry grows not only as a wizard but also as a person under Remus's influence. Another theme could be loyalty. The loyalty between them is often explored deeply, showing how they would stand by each other no matter what. Additionally, there might be a theme of legacy, as Remus passes on his knowledge and values to Harry, who will carry them forward.
Fanfiction.net is also a good place. There are many Harry Potter fanfictions there. Although the interface might not be as modern as AO3, you can still find some great 'Harry is Remus and Sirius cub' fanfictions if you search carefully. Try different combinations of the words in the search bar.
One popular story could be 'The Unlikely Bond'. In this fic, Harry's relationship with Remus and Sirius as a cub - like figure is explored in a heartwarming way. It shows how they take on parental roles and the adventures they have together.
I'm not entirely sure as I haven't read this specific fanfiction. But generally, if Harry is considered Moony's cub, it might be about a special relationship between Harry and Moony (Remus Lupin) where Moony has some sort of paternal or protective role over Harry. It could explore their bond in the context of the wizarding world, perhaps with new adventures or emotional interactions.
I'm not entirely sure as I haven't read this specific fanfiction. But generally, it might be about Harry having some sort of special relationship with Fenrir, perhaps being under his protection or having a unique bond like a 'cub' would with an older, more powerful being in the context of the fanfiction's universe.
Well, without reading it specifically, it might be that 'harry is a cub fanfiction' is a story where Harry is really into the Cubs. It could explore his deep love for the team, perhaps how he got to be a fan in the first place. It might also involve some fictional events related to the Cubs' games or players that Harry is a part of in this made - up story.
Obviously, Harry and Moony (Remus Lupin) are the main characters. Harry is the central character in the Harry Potter universe, and in this fanfiction, he has this special connection to Moony. There might also be other characters from the original series involved, like Harry's friends Ron and Hermione, as they would likely be part of Harry's life and interact with him and Moony.
Sure. You can find them on various fanfiction websites. A lot of these stories play around with the idea of Remus passing on his knowledge of Defense Against the Dark Arts in a more personal way to Harry. It might also involve Harry having to deal with the stigma of having a werewolf father in the wizarding community.