Another plotline could be that in an alternate version of the wizarding world, guns are a common weapon among a group of rebels. Harry joins this group and uses guns to fight against a tyrannical regime within the wizarding community. He might have to overcome his initial aversion to using non - magical weapons and learn to use them effectively while still relying on his magical abilities when necessary.
Maybe Harry discovers a hidden part of the wizarding world that uses guns as a form of magic - enhanced weaponry. So he has to learn how to use these guns in combination with his magic to defeat a powerful villain. For example, the guns could be enchanted to fire spells instead of normal bullets, and Harry has to master this new form of combat.
Another plotline might involve Harry struggling with the moral and ethical differences in the various wars he's fighting in. He could be conflicted about the rules of engagement in some of these new battlefields, which are different from what he's used to in the wizarding world. For example, in a war where non - magical means are also used, he has to figure out how to balance his magical powers with other combat techniques. Also, his relationships with other characters could be explored, like how he forms alliances or rivalries in these new and dangerous situations.
In some fanfics, it could be a competition gone wrong. For example, a friendly sparring match between Percy and Artemis turns into a full - fledged fight due to some external interference like a magic spell or a cursed weapon. This could lead to a series of events where they have to put aside their differences and work together to solve the problem that caused the fight in the first place.
I'm not sure specifically which 'harry fights with guns fanfic' are out there. You could try searching on fanfiction websites like Archive of Our Own or FanFiction.net. Just type in the key phrase 'harry fights with guns' in their search bars and see what comes up.
One possible plotline could be a fight over a love interest. Maybe they both like the same vampire or human and it leads to a physical or verbal fight between Bella and Tanya.
One possible plotline could be Naruto trying to find a way to visit the Harry Potter world. He might search for some kind of magical portal or a powerful spell that can transport him there. Another plotline could be Naruto using the ideas from Harry Potter books to improve his ninja techniques. For example, he could learn about the concept of wandless magic and try to apply it to his chakra control.
A plotline could involve Petunia having a change of heart due to a magical event. For instance, she might accidentally stumble upon some of Harry's magic or receive a message from the wizarding world about his importance. This could lead her to stand up against Vernon and protect Harry. She could then start to teach Harry about his mother's side of the family and the magic that runs in his veins in a more positive way than the Dursleys ever did. And perhaps she even helps him develop his magic skills secretly before he goes to Hogwarts.
One possible plotline could be that Harry, being a wizard from the magical world of Harry Potter, somehow gets involved with the dark and supernatural world of Hellsing. His magical abilities might be a source of both intrigue and conflict. Maybe he uses his magic to help the Hellsing organization in their fight against vampires and other dark creatures, and during this process, he falls in love with a character from Hellsing and they get married.
Perhaps the hickey is a result of a romantic encounter with a mysterious character. And the fic could revolve around Harry trying to figure out his feelings for this person while also dealing with the physical evidence of their closeness. The plot could also involve his friends noticing the hickey and teasing him or being concerned about him.
One possible plotline could be that Harry is cursed and slowly turns into a dragon. As he changes, he has to deal with the physical and mental challenges of this transformation. His friends would try to find a way to reverse the curse while Harry struggles to control his new instincts.
A plotline could involve a Zorua being brought to Hogwarts by a new transfer student from a far - off land. This Zorua has special powers that are not fully understood in the wizarding world of Harry Potter. The student is initially shunned because of the strange creature, but Harry and his friends see the potential good in it. As they get to know the Zorua, they discover that it can help them in their fight against Voldemort. Maybe it can create illusions to mislead Death Eaters or use its shape - shifting abilities to infiltrate their ranks.