Perhaps the plot could revolve around a new threat that requires both the technology of the Stargate universe and Harry's magic to defeat. Harry could teach some of the Stargate personnel basic defensive magic, like Shield Charms. In return, they could introduce him to advanced alien technologies. His ability to apparate could also be a game - changer in certain situations, allowing for quick escapes or surprise attacks on the enemy.
One possible plot is that Harry is somehow transported to the Stargate universe. He might initially be confused but quickly realize that he can contribute with his magical abilities. He could form alliances with the SG - 1 team. Daniel Jackson, who is interested in all things ancient, would be especially intrigued by Harry and his magic. Together, they could explore new planets and try to outwit their enemies.
The plot could involve Harry using his magic in the Stargate universe. Maybe he could use spells to help the Stargate teams in their battles against the Goa'uld. For example, a simple Stunning Spell could be very useful against the Jaffa warriors. He could also use magic to decipher some of the ancient technologies that the Stargate teams come across, since he has experience with ancient magic in his own world.
One idea could be that Voldemort discovers the power of the Stargate and tries to use it to gain more power. He could send his Death Eaters through the Stargate to conquer other worlds and bring back resources or powerful artifacts to help him in his quest to take over the wizarding world. The Order of the Phoenix would then have to follow through the Stargate to stop him.
One possible plot could be that Harry is brought into the SG1 world because of a magical accident involving the Stargate. Once there, he realizes that there are dark forces at work in this universe too. He teams up with SG1 to find a way to get back home while also helping them to stop an impending invasion. Harry uses his Patronus charm to fend off some of the scarier alien creatures, and his knowledge of potions comes in handy when they need to cure a strange alien disease.
A possible plot is that a powerful magical artifact in the wizarding world is actually a key to an ancient Stargate on Earth that has been long forgotten. Harry and his friends, along with the Stargate team, embark on a quest to find this Stargate. Along the way, they face challenges from dark wizards who also want the artifact for their own evil purposes and the Goa'uld who sense the power of the artifact. They must work together, using both magic and technology, to reach the Stargate and unlock its secrets.
One possible plot could be that Hogwarts students discover a Stargate on the school grounds. Maybe it was hidden by a powerful wizard in the past who had visited other planets through it. The students, led by Harry Potter, could then start to explore different planets through the Stargate. They might encounter alien races that have magical abilities similar to theirs, leading to a cultural exchange of magic and technology.
Well, perhaps Harry Potter discovers some ancient magic that has the potential to create a stargate. He might use his knowledge from Hogwarts and the wizarding world to assemble the components of the stargate. Maybe he's on a quest to find a new form of magic or a lost spell that is only accessible through the stargate.
Well, one possibility could be that Harry, through some sort of magical accident or powerful spell, gets transported to the world of Loki. Maybe he initially mistakes Loki for a powerful wizard and tries to seek his help to get back home. Loki, being the trickster he is, might see Harry as an interesting pawn in his schemes against the Asgardians or other foes. Harry, with his own magical skills from the wizarding world, could end up being both a hindrance and a help to Loki, leading to all sorts of adventures and misadventures as they navigate their two very different magical realms.
One possibility is that Harry joins SHIELD after realizing the magical world can't fully contain the threats he's faced. In the fanfic, he could be a key figure in bridging the gap between the magical and non - magical worlds within SHIELD. He might introduce magic - based security measures or use his ability to detect dark magic to identify threats that normal technology can't pick up.
One possible plot for 'harry joins the military fanfic' is that Harry joins the military to find a new purpose in life. He comes from a troubled background and sees the military as a way to discipline himself. He starts in a basic training unit where he meets all kinds of different people from different walks of life. As he progresses, he discovers a hidden conspiracy within the military that threatens national security. Harry then uses his wits and new - found military skills to try and expose the conspiracy and save the day.
In the 'harry joins voldemort fanfic', it could start with Harry being captured by Voldemort. Instead of killing him immediately, Voldemort decides to brainwash him. Through a series of dark magic spells and psychological manipulation, Harry starts to see Voldemort as a mentor. As time passes, Harry becomes an integral part of Voldemort's inner circle, helping him plan attacks against the wizarding world, believing that they are actually for a greater good as Voldemort has convinced him.
Well, one possible plot could be that Harry Potter discovers a Stargate during his travels. He then gets transported to a new world where he encounters a group of powerful and diverse characters who form a harem around him. They all have different magical abilities from both the Harry Potter universe and whatever new universe the Stargate leads to. Together, they embark on a journey to stop an evil force that threatens both worlds.