A great Saint Tail fanfiction idea could be one that delves into her origin story more deeply. What if there were more details about how she learned her skills? How did she choose the name Saint Tail? This kind of fanfiction would give readers a better understanding of the character's backstory and motivation.
One idea could be exploring the backstory of a Wizard Saint. For example, how they came to achieve such a high rank in the Fairy Tail universe. Maybe they had to overcome a great personal tragedy or a powerful enemy.
One interesting Naruto Saint fanfiction could be one where Naruto discovers a new sage mode that combines the powers of different saints. This would give him enhanced abilities like super speed and strength, as well as unique jutsu.
One interesting Fairy Tail fanfiction could be about an alternate universe where the main characters have different magic abilities. For example, Natsu might have ice - based magic instead of fire. Another could focus on the backstories of the minor characters in more detail, like how Jet and Droy met before joining Fairy Tail.
One interesting Saiyan tail fanfiction could be about a Saiyan who discovers a unique power related to their tail. For example, the tail can be used to sense danger from afar, much like an extra sense organ. This could lead to adventures where the Saiyan uses this ability to protect their friends and planet.
One interesting Inuyasha tail fanfiction could be about how Inuyasha's tail has a special power that he discovers during a battle. Maybe his tail can sense danger before it arrives and it starts to twitch, warning him and his friends. Another could be a story where his tail is the key to unlocking an ancient spell that has been long forgotten in the Feudal Era.
One interesting story could be about a character's journey in the far corners of the ASOIAF world that wasn't explored much in the original. For example, a story about a minor character from a small village who discovers a hidden power.
A great Fairy Tail fanfiction might be one that gives a different ending to a major arc in the series. Instead of how it ended in the original, it could have a more bittersweet or even a completely different resolution. For instance, in the Tartaros arc, it could end with a different sacrifice or a new way of defeating the demons.
One interesting Fairy Tail fanfiction could be about an alternate universe where the characters have different magic abilities. For example, Natsu might have ice - based magic instead of fire. Another could focus on a romantic relationship between two characters that wasn't explored much in the original, like Levy and Gajeel's relationship in more depth.
A 'Harry Potter Saint fanfiction' might focus on a single character from the Saint series ending up in the Harry Potter world. Let's say Pegasus Seiya. He could be mistaken for a new kind of wizard and be enrolled in Hogwarts. He would struggle with the normal wizarding curriculum like Potions and History of Magic while also trying to find a way back to his own world. His presence could also inspire some of the Hogwarts students to be braver and more determined in the face of danger.
One interesting story could be one that focuses on the character development within the Fairy Tail universe while still having a touch of the unique elements from 'Lemons Fanfiction'. For example, a story about a secondary character getting a chance to shine and their relationships evolving in a way that's not shown in the original series. However, it's important to note that 'Lemons' often implies more adult - themed content, so many platforms may not allow such explicit fanfictions.