Well, a lot of them have the theme of breaking barriers. In the wizarding world, there are social and personal barriers between Harry and Filch. Fanfictions often explore how they overcome these. Also, the theme of understanding is prevalent. Harry and Filch come from different worlds within Hogwarts, and through their friendship, they learn to understand each other's perspectives. This can be really interesting as it shows growth in both characters.
Sure. In some fanfictions, the author might create a scenario where Harry discovers that Filch has a softer side. For example, Filch could be secretly protecting a magical creature on the Hogwarts grounds, and Harry stumbles upon this. This shared interest in the creature could be the start of their friendship. It's these kinds of creative plotlines that make 'Harry friends with Filch' fanfictions so engaging.
One possible plot could be that Harry catches Filch in a vulnerable moment. Maybe Filch has lost something precious, and Harry helps him find it. This act of kindness makes Filch see Harry in a new light, and they gradually start to become friends. Harry could then learn more about Filch's past and the reasons behind his strict nature.
I'm not sure of a specific 'Harry friends with Filch' fanfic off the top of my head. But you can try searching on popular fanfic websites like Archive of Our Own. They usually have a wide range of fanfics based on different themes and relationships, and you might find one that focuses on Harry and Filch becoming friends there.
Since we only have the title 'mister little cave story', the 'mister' could be a variety of characters. It could be an old hermit who has made the little cave his home. Or it could be a young adventurer who is exploring the area and stumbles upon the little cave. Another possibility is that 'mister' is a scientist who is studying the cave for geological or ecological reasons.
Draco Malfoy and Argus Filch are the main characters. In these fanfictions, Draco might be exploring the secrets of the collar out of curiosity or for some devious plan. Filch, on the other hand, is protective of his collar as it might hold sentimental value or some power that he doesn't want to be misused. There could also be minor characters like the Weasley twins. They could be causing additional chaos while Draco is dealing with the collar situation, perhaps using it as an opportunity to play more pranks in Hogwarts.
In a more serious fanfiction, the collar could be a family heirloom of Filch's that has been passed down for generations. Draco accidentally stumbles upon its significance and realizes that it is the key to unlocking a long - forgotten secret about Hogwarts. He then has to decide whether to share this discovery with Filch or keep it to himself for his own gain.
Mister X in 'hire mister x game dev story' is a mystery. He could be a veteran in the game industry with years of experience and a wealth of knowledge. He might have worked on some of the most iconic games in the past. Or he could be a young and upcoming talent that the game dev team in the story has spotted. Maybe he has some special skills like creating hyper - realistic graphics or writing complex and engaging game narratives. Without more context, it's hard to determine exactly who he is.
I recommend the modern romance novel "Overbearing Young Master Li, Spoiling the Heavens". The male lead was a cold and fickle big shot. The female lead liked to call him Mr. Li, and he doted on her very much. I hope you like this fairy's recommendation. Muah ~😗