The Stargate could be a portal between different magical realms in the Harry Potter universe. For example, it could lead to a place where ancient and more powerful magic exists. Wizards from different schools around the world could team up with Stargate explorers to uncover the secrets of this new place. There might be a new threat emerging from this realm that requires both magic and Stargate technology to defeat. This would bring together characters like Harry Potter and Jack O'Neill to lead the charge against the common enemy.
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 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 idea could be that the Death Eaters in Harry Potter form an alliance with the Goa'uld from Stargate SG1. The combined forces of dark magic and alien technology would be a huge threat. The heroes would then have to combine their skills, with the wizards using spells to counter the Goa'uld's energy weapons and the SG1 team using their military tactics against the Death Eaters. Another idea is that the Hogwarts students go on a field trip through the Stargate. They encounter various alien races and have to use their magic to survive and make friends. This could be a great way to show how magic can be applied in a completely different setting.
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, perhaps the magical creatures from the Harry Potter universe end up in the '300' setting. Dragons could be used by the Spartans to fight their enemies. The centaurs could also join the battle, lending their archery skills. And Harry could learn some combat skills from the Spartans, which he could then use back in the wizarding world to fight Voldemort's Death Eaters.
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.
Well, perhaps there's a rift in the multiverse that connects Central City to Hogwarts. The Flash, while chasing a villain, gets sucked into the wizarding world. Harry Potter and his friends initially suspect him as a threat but then realize his good intentions. They then combine their powers - the Flash's speed and the magic of the wizards - to fight a common enemy. For example, the Flash could use his speed to distribute protective spells all over Hogwarts really quickly, while Harry and his friends focus on the offensive magic against the bad guys.
One idea could be that Carly and her friends discover a magical portal in their apartment that leads to Hogwarts. They then have to navigate the wizarding world, with Carly being fascinated by all the magic. Meanwhile, Harry Potter and his friends are intrigued by the strange Muggle - like devices the iCarly gang has. They end up teaming up to solve a mystery that involves both the wizarding and Muggle worlds.
Well, perhaps the Death Note from the Bleach universe gets mixed up with the magic in Harry Potter's world. A powerful wizard could get hold of it and start using it in ways that disrupt the balance of life and death in both worlds. Harry and his friends would have to figure out how to stop this misuse, with the help of some Bleach characters who understand the true nature of the Death Note.
One idea could be that Eragon, while on one of his adventures in Alagaësia, accidentally creates a portal that leads him to Hogwarts. There, he meets Harry Potter and they quickly realize they have a lot in common. They could team up to fight against a dark force that somehow threatens both their worlds, like a new type of dark magic that combines the magic of Alagaësia and the dark arts from the wizarding world.