Well, a possible plot might be that Harry's resemblance to Lily makes him a target for some magical creatures that were associated with her. Maybe there's a magical being that was bound to protect Lily and now mistakes Harry for her. Also, in the wizarding world, there could be portraits or ghosts that react strongly to Harry's appearance, leading to some revelations about Lily's past that no one knew before.
Perhaps a fanfic where Lily Potter's spirit is able to communicate with Harry Potter during his difficult times at Hogwarts. She gives him advice and guidance that helps him through his struggles, like dealing with Snape's complex feelings towards him, or facing the challenges of the Triwizard Tournament. This would add an emotional and magical element to Harry's journey.
One idea could be a story where Harry and Lily Luna Potter time - travel together. They could go back to the time when the Marauders were at Hogwarts and have all sorts of adventures, like helping Sirius and James avoid getting into trouble with Snape. Another plot could involve them facing a new dark wizard threat in the future. Lily Luna could show her own brand of magic, different from Harry's but equally powerful, as they team up to defeat the enemy.
One idea could be a time - travel plot where Harry somehow gets to meet Lily in a parallel universe. They could bond over their shared magical abilities and family traits.
One idea could be Lily Luna Potter discovers a hidden spellbook that once belonged to Harry Potter. She starts to experiment with the spells inside and accidentally opens a portal to a parallel magical world. There, she meets a younger version of Harry Potter and they have to work together to find a way back home while also facing the new and strange magical threats in that world.
One plot idea could be that Lily, Luna, and a character named Lemon discover a hidden spell in the Forbidden Forest that has a connection to Harry Potter's past. They embark on a journey to understand the spell's significance and how it might affect the wizarding world's future.
A really interesting plot could be that James and Lily, alive, work with Dumbledore to create a new school of magic. This school would focus on teaching students how to defend against the Dark Arts in a more practical and hands - on way. Harry would be one of the first students there. They could also develop new magical artifacts that could help in the fight against evil. And the family could have adventures all over the world to find the ingredients and knowledge needed for these new creations.
One interesting plot idea could be that Lily and James, alive and well, decide to train Harry in magic from a very young age. This would make Harry an even more powerful wizard earlier on. They could also use their influence to reform the wizarding world, starting with Hogwarts. For example, they might introduce new courses that focus on both light and dark magic, teaching students how to defend against the dark arts in a more comprehensive way.
One idea could be that in this fanfiction world, because of the physical resemblance, Harry is often mistaken for a descendant of Tom Riddle in a more positive light than in the original series. This could lead to some witches and wizards believing he has the potential for great power without the dark taint. For example, he might be offered special training by some old wizarding families who want to use his supposed connection to Riddle for good. Another plot could involve Harry using this resemblance to infiltrate a group of Death Eaters who are trying to revive Voldemort in a new way. He could pretend to be on their side, learn their secrets, and then expose them.
One idea could be that Harry discovers the truth about his parentage early on. This changes his relationship with Dumbledore as he realizes Dumbledore had been keeping this big secret from him. He might also struggle with his identity, feeling torn between the Gryffindor ideals he was raised with and the Slytherin traits he might inherit from Snape.
A possible plot could involve an alternate universe. In this universe, Lily doesn't end up with James Potter. Harry, being from his own universe, arrives in this one and meets Lily. They initially bond over their shared magical abilities and a sense of not quite belonging. As they spend more time together, they develop feelings for each other, which is a huge shock to Harry at first as she is his mother in his own universe.