In some fanfictions, the sword chooses Harry. It could appear out of thin air in front of him when he's in a moment of great need, like when he's surrounded by a horde of Death Eaters. The sword might sense his courage and determination and decides to come to his aid.
He might find it in a hidden chamber in Hogwarts. There could be a series of magical puzzles and traps that he has to overcome to get to it.
In many Harry Potter - related stories, the sword of Gryffindor often finds its way to those who are worthy. Maybe in this fanfiction, Harry discovers it in a similar way. It could be hidden in the Sorting Hat, or perhaps it's presented to him by some magical creature that recognizes his need and his courage.
Perhaps it is given to him by a mysterious figure. This figure could recognize Harry's potential and believe that he is the right person to wield the trident. The figure might be from a different magical culture that has a connection to the trident and sees Harry as a key to some greater purpose.
Well, in some fanfictions, the legendary sword might be enchanted with special powers like being able to cut through any dark magic. It could also have a mind of its own and only allow Harry to wield it when he's in a pure - hearted state.
In this fanfiction, Harry Potter could obtain Gungnir in a rather unexpected way. For example, due to a time - traveling incident. He might accidentally travel to a different time and place where Gungnir exists. There, he could be in a situation where he has to help the local magical community. As a result of his heroic deeds, the keepers of Gungnir decide to entrust him with it. And when he returns to his own time, he brings Gungnir with him, ready to use it in his fight against the dark forces.
Another way could be through inheritance. Maybe it was his father's or some distant relative's weapon. However, it was sealed away for safety reasons. As Naruto grows stronger and faces greater threats, the weapon reveals itself to him. It's as if the weapon senses that Naruto is the right person to wield it at that crucial moment.
Yes, there are many. In some fanfictions, the sword might have the power to cut through any dark magic. For example, it could be able to destroy Horcruxes more easily than in the original story. It might also have the ability to protect the wielder from the most powerful curses.
They might find them in hidden chambers. In some fanfics, the sword and shield are hidden deep within an ancient wizarding castle, and only those with a pure heart can discover them. It could be like a test of character where the character has to overcome a series of magical traps and puzzles to get to them.
Well, it could potentially give him an edge in combat. Maybe he can use it to defeat dark creatures more easily. For example, if he faces a Dementor, the sword might be able to disrupt its form in a way normal spells can't.
Maybe it was given to him by a mysterious stranger. This stranger could be someone who has been observing Harry from afar and believes that he is the only one who can handle the power of the hand cannon. The stranger appears out of nowhere, hands it to Harry, and then disappears again without a trace.
Harry Potter himself is often associated with it. After all, he's the main character in the original series and it makes sense for him to be connected to the legendary sword in fanfictions. He could use it to fight Voldemort in new and exciting ways.