A great plot idea could be that the female basilisk is actually a guardian of an ancient wizarding secret. Harry stumbles upon her while exploring a hidden part of Hogwarts. Instead of fighting, they form an alliance to protect the secret from dark wizards who are also seeking it. This would focus on mystery, adventure and cooperation rather than any inappropriate themes.
One plot idea could be that the male basilisk is actually a cursed wizard who can only take the form of a basilisk. Harry discovers this and tries to find a way to break the curse. Another could be that the basilisk has a special power that can help Harry in his fight against Voldemort, so they form an alliance.
One idea could be that a female Harry Potter discovers a time - travel spell and goes back in time to try and prevent Voldemort from ever becoming evil. She could try to befriend him as a child, show him kindness, and change the course of history. This would create a very different wizarding world and an interesting dynamic between the two characters.
Yes, there are likely many 'Harry and male basilisk' fanfictions that don't have lemon (adult or sexual) content. You can try searching on fanfiction - specific websites like FanFiction.net or Archive of Our Own. Use the search filters to exclude mature content if available.
Well, here's another plot. Madam Malkin could be visited by a strange wizard who tries to put a curse on her shop. Harry, being the hero he is, comes to her rescue. As they try to figure out who the wizard is and why he targeted the shop, they have to rely on each other's skills and knowledge. This not only shows their friendship but also creates an exciting adventure - filled story.
A plot could involve Female Naruto being an outcast in the village because of her different way of doing things. Minato, as the Hokage, takes an interest in her and decides to train her personally. He discovers that she has a unique chakra nature that no one has seen before. They embark on a journey to understand this chakra and in the process, they form a strong bond of friendship and mutual respect. Along the way, they face opposition from some of the more traditional villagers who are skeptical of Female Naruto.
A cool plot could be that Female Hidan is actually an undercover agent for a village that is trying to take down the Akatsuki from the inside. Naruto discovers this and they have to work together secretly to achieve their goal while not being caught by the other Akatsuki members.
A great plot idea could be that the Basilisk was not just a mindless monster but was actually being controlled by an unseen force all along. This force could be an ancient spirit or a powerful dark wizard from the past who was using the Basilisk to carry out their evil plans. Harry and his friends would then have to not only defeat the Basilisk but also uncover the identity of the mastermind behind it. Another plot could be about the Basilisk's venom. What if there was a way to use the venom for good, like creating a powerful antidote to a new and deadly dark magic spell? The characters would have to figure out how to safely extract and use the venom without getting killed by the Basilisk.
One idea could be that a centaur saves Harry from a dangerous creature in the Forbidden Forest and then they form a bond. The centaur could teach Harry about the ancient magic that the centaurs possess. Another plot could be a centaur acting as a guide for Harry during his search for a rare magical herb that only grows in centaur - protected areas. They would have to work together to overcome various obstacles.
One idea could be that a Succubus is a new kind of magical creature discovered in the Forbidden Forest. The Hogwarts students and professors have to figure out how to deal with it, whether it's a threat or not. Another could be a Succubus who has lost her powers and comes to Hogwarts seeking help to regain them in a non - sexual way, like learning about different kinds of magic.
One idea could be that Wanda Maximoff is transported to the Harry Potter universe. She could use her powers to help Harry and his friends during the Battle of Hogwarts. Her ability to manipulate energy and reality could give them an edge against Voldemort and his Death Eaters.