Well, it could be that Harry Potter is frozen in cryogenic state to preserve him from a dark magic threat. When he is finally unfrozen, he has to adapt to a new Hogwarts where the rules and students have changed a great deal. He might find that some old spells don't work the same way anymore and has to learn new ways to combat the dark forces that still lurk.
In a 'Harry Potter frozen in cryogenic' fanfic, it could be that an experiment by some eccentric wizard goes wrong. Harry Potter gets caught in the crossfire and is frozen. When he wakes up, he finds himself in a different era of the wizarding world. He teams up with some new characters who are descendants of his old friends. Together, they try to solve the mystery of what went wrong in the experiment and prevent a similar catastrophe from happening again.
Maybe Voldemort has won a great battle and in a last - ditch effort to save Harry, Dumbledore freezes him in cryogenic state. Years pass and the wizarding world has become a desolate place under Voldemort's rule. When Harry is thawed, he discovers he has some new and unexpected powers that are the result of the cryogenic process, and he uses these to start a revolution against Voldemort.
It could be a descendant of Voldemort. Even though Voldemort was defeated in the original series, his ideas might have been passed down through generations. This new villain could be even more cunning and powerful, and they see Harry Potter, who has been frozen and is now back, as a threat to their plans of total wizarding world domination.
In this fanfiction, it might be that a powerful dark magic spell backfires and freezes Harry in time. His friends, Hermione and Ron, would then embark on a journey to find ancient magic that can reverse the spell. They might have to search through old wizarding libraries and consult with long - forgotten magical creatures. This would be a great adventure full of mystery and discovery. Also, they would face many challenges along the way, like avoiding the Ministry of Magic which might want to study Harry in his frozen state instead of helping him.
A possible plot is that a dark wizard from the Harry Potter world tries to take over Arendelle. Elsa and Anna have to team up with Harry and his friends to stop this threat. The Frozen characters would be introduced to the concept of the Deathly Hallows and Horcruxes. Elsa's ice powers could be a key factor in fighting the dark magic. Maybe her ice can counter some of the dark spells, and together they all discover new ways to combine their unique abilities to defeat the evil wizard.
The fanfic could center around Harry's life outside of the main events of the books. For example, it could explore his summer holidays in more detail. He could be spending time in the Muggle world and using his magic in creative ways to solve normal, everyday problems. He might use magic to help his neighbor fix a broken fence without the neighbor realizing it was magic. This would add a new dimension to his character and show how he can adapt his magical abilities to different situations.
One possible plot could be that Harry Potter is hired by Sherlock Holmes to help with a case that involves dark magic. Harry uses his knowledge of the wizarding world to uncover clues that Sherlock couldn't find with just his deductive skills.
Imagine Harry Potter as a bartender. He could be using his skills not just in mixing drinks but also in reading people. Since he has faced so many challenges in his life, he can easily spot if a customer is hiding something or if they are in trouble. His bar could become a place where secrets are shared, and he has to use his wits and magic to keep things in order. He might also have to deal with rival bartenders from other wizarding establishments who are jealous of his popularity and unique drinks.
The plot could involve Harry Potter discovering he has some sort of connection to a dragoness. Maybe he can communicate with her telepathically. They could team up to fight against dark forces in the wizarding world. For example, Voldemort might be after the dragoness for her powerful magic, and Harry has to protect her while also using her strength to defeat Voldemort.
One possible plot could be a deaf Muggle - born student getting their Hogwarts letter. They face difficulties in the beginning as they can't hear the instructions well. But they soon discover a magical device that helps them 'hear' in a magical way, like through vibrations that translate into words in their mind. Then they go on to prove themselves in classes like Charms and Potions, making friends along the way.
Well, it could be that Harry discovers a hidden chamber in Hogwarts that has Xenomorphs in it. Maybe he has to use his magic to fight them off or find a way to co - exist.
Well, perhaps the Hitman gets transported into the Harry Potter universe by some sort of magic accident. He then uses his combat and assassination expertise to help Harry Potter and his friends in their fight against Voldemort. He could teach them some non - magical ways of combat and they could teach him about magic in return. This would create an interesting dynamic between the Muggle - like Hitman and the magical characters.