Maybe he uses some special ingredients that others don't usually consider. For example, he might find a rare herb in the Forbidden Forest and use it in a potion to enhance its effect.
The Polyjuice Potion was used to disguise a wizard as another person. After drinking the Polyjuice Potion, not only would their face and body change, but their gender, scars, tattoos, voice, and even physical defects could be completely replicated. However, Polyjuice Potion could only be used to transform humans. It could not be used to disguise non-human creatures, or there would be magical accidents. In addition, depending on the degree of brewing of the Polyjuice Potion, the effect may last for 10 minutes to 12 hours. Harry Potter and the Goblet of Fire was not enough. Everyone, please click to read the novel!
In the fanfic, perhaps there's an event where Harry discovers a new potion ingredient while exploring the Forbidden Forest. He then uses this ingredient to create a unique potion that has never been made before in Hogwarts. This discovery not only showcases his skills but also earns him respect from the potions community in the school. Also, he might be asked to help Snape with a difficult potion - making task for an important event, like a visiting wizard dignitary.
The Polyjuice Potion consisted of lacewings (20 - 21 days), leeches, horns of bicorns (ground into powder), two-ear grass, liquid grass (plucked at full moon), skin of African Boomslang, and a little bit of the person you wanted to turn into (such as hair, dandruff, or nails). Harry Potter and the Goblet of Fire was not enough. Everyone, please click to read the novel!
Polyjuice Potion was a potion from the novel Harry Potter. The recipe was described in the book, The Potion of Power, which was kept in the restricted section of the Hogwarts library. This potion could only be used for human transformation. The Polyjuice Potion has been a driving force in the Harry Potter series many times. For example, in Harry Potter and the Chamber of Secrets, when Harry Potter and the others suspected that Draco Malfoy was the true heir of Slytherin, Hermione discovered the formula of Polyjuice Potion. They used the Polyjuice Potion to disguise themselves as Malfoy's good friends Crabbe and Goyle to get information, but Hermione accidentally turned herself into a cat. In Harry Potter and the Goblet of Fire, Barty Crouch Jr. used Polyjuice Potion to transform into Professor Alastor Moody, imprisoning the real Moody to ensure the continuous source of the potion, and thus undercover at Hogwarts; After Voldemort took control of the Wizarding world, Harry became the number one "wanted criminal". Before his seventeenth birthday, his friends used Polyjuice Potion to send him from Privet Drive to Grimmauld Place. During the Battle of the Seven Potters, his friends disguised themselves as Harry to confuse the Death Eaters. Although this potion had a high practical value, it required a high level of skill to brew, and it would take a whole month to brew it perfectly. Harry Potter and the Goblet of Fire was not enough. Everyone, please click to read the novel!
Severus Snape is another character who could be considered a potions genius in fanfic. In the official story, he was a master of potions. Fanfic writers might explore more of his early days as a potions prodigy or create scenarios where he imparts his deep knowledge of potions to other characters in unique ways.
Neville Longbottom's Potionology grades were worse. He struggled in Potions, which Professor Snape often accused of being a "terrible" subject. Harry Potter and the Prisoner of Azkaban wasn't enough. Everyone, please click to read the novel!
In the fanfiction, Draco's shop could have a special love potion. However, it's not the regular love potion but a more refined version that has a milder effect. Also, there could be a potion that helps with sleep, which is much needed for those who have trouble sleeping due to nightmares caused by dark magic.
Hermione is often a common character. She might be helping Harry with research related to the potions professor's strange behavior or new potions they are working on. For example, she could be scouring the library for information about a rare ingredient the professor has introduced.
There are also some original characters created in fanfiction who are potion geniuses. These characters can bring new storylines and perspectives to the world of Harry Potter potions. They might have unique ways of brewing potions or discover new potion recipes that change the magical world.