In the 'harry gets a gun fanfiction', it could be that Harry is given the gun by a mysterious figure. This figure might have an ulterior motive, like using Harry as a pawn in a bigger game. Harry then has to decide whether to trust this person and what the implications of having the gun are for his own safety and the safety of those around him.
A wizard who has dabbled in the Muggle world might give Harry a gun. This wizard could have seen the potential use of a Muggle weapon in the wizarding world's dangerous situations.
In this fanfiction, Harry might have the gun as a gift from a mysterious figure. The gun could have special powers like it can only be fired by him and the bullets can penetrate any protective spell. This would lead to a whole new set of adventures as he tries to figure out the origin and purpose of this unique weapon.
Perhaps it's a story where Harry Potter is transported to a world that combines elements of the wizarding world and a modern, gun - using society. He pulls a gun to protect his friends when they are attacked by some unknown and powerful force that magic has no effect on. This could lead to him having to learn about the new rules and ethics of using such a weapon while still relying on his magical abilities.
In the 'harry gets a tattoo fanfiction', he might get a tattoo as part of a bet or a dare. His friends challenge him and, being the brave Harry we know, he accepts. The tattoo could be something really out - of - the - ordinary, like a moving image of his Patronus. This could lead to all sorts of adventures as he tries to hide it from the more conservative members of the wizarding world.
In this fanfiction, perhaps Harry saves a girl from a dangerous magical creature during one of his adventures outside of Hogwarts. She's so grateful and as they spend more time together healing her wounds and such, they develop feelings for each other.
Well, perhaps Voldemort's followers could kidnap Harry to use him as a bargaining chip. They might hold him in an old, dark wizarding house, guarded by dark magic. Harry would then try to escape using his own magic skills and the help of some unexpected allies like house - elves who secretly oppose Voldemort.
Maybe it could be about Harry's insecurities at first with getting braces. He might be worried about how his friends will react, especially if he has a crush on someone at Hogwarts. But then as the story progresses, his friends support him and he learns to embrace his new look.
In a 'Harry Potter gets emancipated' fanfiction, the plot could involve Harry getting emancipated due to his special status as the Boy Who Lived. With his emancipation, he could take charge of his own finances, which were a mess in the hands of the Dursleys. He could then use his money to fund independent research on dark magic defenses. Maybe he'd even start a small group of like - minded students who are also frustrated with the slow - paced and sometimes - inaccurate teachings at Hogwarts.
Maybe Ginny did something that Harry thought was a betrayal, like siding with someone against him in a wizarding conflict. So Harry decides to play some harmless pranks on her to get revenge. For example, he might use magic to make her quill write silly things during a class.
Well, perhaps Harry discovers a magical creature in the Forbidden Forest that becomes his familiar. It could be a small dragon-like creature that only he can communicate with, and it helps him find hidden secrets in Hogwarts.