Perhaps there could be a plot where a spell gone wrong in the Harry Potter world creates a rift that pulls in the Date A Live world. The main characters from both universes then have to find a way to close the rift. During this time, the characters from Date A Live are introduced to magic and the characters from Harry Potter are introduced to the concept of spirits. They exchange knowledge and skills to overcome the challenges they face.
One possible plot could be that the Date A Live characters somehow end up in the Harry Potter universe. Maybe they are there to stop a new kind of threat that combines the magic from the Potter world and the spirits' powers from Date A Live. The wizards are initially suspicious of them but then realize they need to work together.
One possible plot could be that Naruto and his friends are somehow transported to the world of Date A Live. Naruto, with his determination and never - give - up attitude, could team up with Shido to fight against the Spirits that are causing chaos. Maybe Naruto's jutsu can be used in unique ways to deal with the Spirit - related problems, like using his Shadow Clone Jutsu to distract the Spirits while Shido tries to seal them.
In a 'Naruto in Date A Live' fanfiction, Naruto could be a key figure in preventing a total war between the Spirits and humans. His ability to understand and empathize with outcasts (like he did with Gaara) could help him communicate with the Spirits on a deeper level. He could teach Shido some of his ninja techniques to better protect the Spirits and also use his own chakra to help stabilize the space - quakes caused by the Spirits, thus bringing a new hope for peace in the Date A Live world.
One idea could be exploring an alternate universe where the Spirits and the main character have different initial meetings. For example, instead of meeting in a battle - like situation, they meet in a peaceful school event. Another plot could involve a Spirit who has lost her powers and the main character has to help her regain them without using the usual methods. It could lead to a whole new adventure and deeper understanding between them.
One idea could be that during a Quidditch match, a player gets seriously injured. Instead of using magic to heal right away, an ambulance from the Muggle world is called in by a confused bystander. The ambulance crew has to deal with the magical aspects they've never seen before while trying to transport the patient to a Muggle hospital. This could lead to a lot of comical and also tense situations as they try to figure out how to handle the situation.
One idea could be a wizard discovers Beyblades in the Muggle world and decides to bring them to Hogwarts. He then challenges his classmates to Beyblade battles instead of duels. The different houses could form their own Beyblade teams and compete in a tournament, with the winning house getting extra house points and a special magical Beyblade as a prize.
One possibility could be that Supergirl somehow ends up in the wizarding world of Harry Potter. Maybe she's chasing a powerful magical artifact that has fallen into the wrong hands in Hogwarts. She could use her superpowers to help Harry and his friends during a particularly tough battle against Voldemort, like using her heat vision to fend off Dementors or her super strength to break through some dark magic barriers.
One idea could be Harry using parkour skills to escape from the Death Eaters in the Forbidden Forest. He jumps from tree to tree, slides under fallen logs, and uses his magical abilities in combination with his newfound parkour skills to outmaneuver them.
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.
Well, it could start with Harry nervously asking Ginny to meet him at the Hogwarts grounds. Maybe they go for a walk by the lake, holding hands and sharing stories. They could end up at the Astronomy Tower, looking at the stars and having a really deep conversation about their future together.
One idea could be that the Justice League somehow ends up in the wizarding world. Maybe a magical portal opens during a battle in their universe and sucks them into Hogwarts. Superman's powers could be affected by the magic there, and Batman would be intrigued by the complex magic system and start studying it. Harry Potter and his friends could team up with the Justice League to fight a new dark force that threatens both the magical and non - magical worlds.