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.
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.
He could get them from his Muggle relatives. Since he spends time with the Dursleys, there might be a situation where he stumbles upon some of their tools or weapons, like a gardening hoe that he could potentially use as a weapon in a fight. Another way is through his Muggle - born friends at Hogwarts. They might bring in some items from the Muggle world that Harry then takes an interest in and decides to use.
He might inherit some of the cars. For example, he could inherit a classic wizarding car from his parents' old friends. Another way could be that he wins them in magical contests. There could be a Triwizard Tournament - like event where the prize is a unique and powerful car.
He might find it in a hidden chamber in Hogwarts. Maybe it was left there by a powerful wizard from long ago who had some connection to other universes.
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.
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.
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 some fanfictions, he might find it in the Forbidden Forest during one of his adventures. Maybe while exploring the deeper parts of the forest that are off - limits to most students, he stumbles upon a young pegasus in need of help. Harry, being the kind - hearted person he is, bonds with the pegasus and it becomes his familiar.