One possible storyline could be that the fairy dog is a gift from Dumbledore. It has the ability to sense dark magic and helps Harry detect threats before they become dangerous. For example, it could sniff out a hidden Death Eater's spell.
Common themes often include magic and mystery. The fairy dog usually has some special magical powers that are a mystery to be uncovered. Also, the theme of loyalty is present as the dog is loyal to Harry. In these fanfictions, the dog might also represent a new form of magic in the wizarding world that Harry has to learn about and adapt to in his fight against the dark forces.
Another idea is that there is a prophecy that requires Harry's early death to save the wizarding world in a different way. He discovers this prophecy and, being the selfless hero he is, willingly accepts his fate. His death then triggers a series of events that lead to a new era of peace and harmony in the wizarding community, but his friends and allies still deeply mourn his loss.
One interesting 'Young Harry Potter Fairy Dog Fanfiction' could be 'The Adventures of Harry Potter and the Magical Fairy Dog'. In this fic, the fairy dog might be a new magical creature that Harry discovers during his time at Hogwarts. It could have unique powers like being able to sense dark magic from afar and helps Harry in his quests to defeat Voldemort.
One possible storyline could be a character getting hit by a powerful dark spell during a battle, which causes brain damage. Then the story could revolve around their struggle to regain their magical abilities and memories. For example, if Harry were to be the one with brain damage, he might have to relearn spells and how to interact with his friends in Hogwarts.
One possible storyline is that the Potter Manor is under attack by a new dark force. Harry and Ginny have to defend it using their skills and the help of their friends. Another could be that they are renovating the manor and discover some long - lost family secrets during the process.
A possible storyline is that Ruby Rose, with her combat skills, trains the students at Hogwarts in self - defense against the dark arts. Harry Potter might be initially skeptical but then realizes the value of her unorthodox methods.
One storyline could be that Harry, after the events in the wizarding world, decides to take a break and travels to Gotham. There he meets Bruce, and they end up teaming up to take on a new threat that combines magic and Gotham's usual criminal element. Maybe a villain who has somehow gotten hold of a powerful magical artifact and is using it to wreak havoc in the city.
One possible storyline could be that the hobgoblin is a magical creature that has been trapped in Hogwarts for centuries and Harry discovers it. The hobgoblin then teams up with Harry to uncover the secrets of Hogwarts that are related to a new dark threat. Another could be that the hobgoblin is a messenger from an unknown magical realm and it chooses Harry to be the one to communicate with its realm.
Well, it could be a story where Harry is tricked into believing that Muggles are responsible for some great harm to his loved ones in the wizarding world. So, in his rage and misdirected sense of justice, he starts targeting Muggles. But this is a very un - Harry - like behavior as the real Harry is all about protecting the innocent, whether they are wizards or Muggles.
One possible storyline could be Harry growing up in Gotham, learning Batman's ways, and then suddenly discovering his wizarding heritage. He would have to adjust to the magical world while still holding onto his Batman - trained values. Another could be that Batman somehow ends up in the wizarding world and has a relationship there, resulting in Harry. Then the story could focus on how Harry uses his father's skills to combat dark magic.