Perhaps in the fanfic, Harry is turned into a snake for a period of time. As a snake, he experiences the wizarding world from a different perspective. He has to learn how to survive as a snake while still trying to fulfill his role in the fight against Voldemort. He might encounter other snakes that are either friendly or hostile, and he has to use his wits to deal with them.
Perhaps the snake is a transformed wizard who was cursed. This would lead to a plot where Harry has to find a way to break the curse. He might have to go on a quest to find rare ingredients for a potion. Along the way, he and the snake face various challenges, like dark wizards trying to stop them, and they form a strong friendship through their shared experiences.
In this fanfic, it could be that Harry turns into a snake as a result of a powerful transfiguration spell gone wrong. As a snake, he has to navigate the Hogwarts grounds in a new way. He might find secret passages or areas that are only accessible in his snake form. His friends, like Hermione and Ron, would then try to find a way to reverse the spell, and there could be a lot of trial and error, as well as some really heart - warming moments of friendship along the way.
One possible plotline could be the discovery of a new type of deadly snake in the Forbidden Forest that has some mysterious connection to dark magic. Maybe the snake is guarding a long - lost artifact.
Perhaps there's a plot where a magical creature that has the appearance of a snake is disguised as a lion - like being. It could be used as a sort of spy within the Gryffindor common room. This would lead to all sorts of chaos as it tries to gather information for an unknown Slytherin - related plot.
Well, a plotline might involve the snake familiar getting into trouble. For example, it could be mistaken for a dark creature by the Ministry of Magic. Harry then has to prove that his snake is not evil. Or perhaps the snake helps Harry discover a hidden part of Hogwarts. Since snakes are often associated with secrets, it could lead him to a secret chamber or passage that no one else knows about. And this could be a key to solving a mystery or finding a powerful magical item.
Well, one plotline could be the main character, perhaps a new healer at Hogwarts, dealing with magical maladies that are beyond the usual. For example, they might encounter a spell - induced illness that spreads among the students and has to find a unique cure using both traditional and forgotten healing methods.
Since this is an improper concept for the Harry Potter world, there are no so - called 'good' plotlines in such fanfic. We should uphold the positive values that J.K. Rowling intended in the original work, rather than exploring such unseemly fan - created ideas.
Well, perhaps in 'the king harry potter fanfic', there's a plotline where Harry discovers a long - lost magical artifact that gives him the power and status of a king. This could lead to him having to face off against old enemies who now see him as an even greater threat. And his friends from Hogwarts might have to band together to protect him as he adjusts to this new role. Also, it could involve new magical creatures being drawn to him because of his new - found king - like aura.
A great plotline in some fanfics is the discovery of new spells and magic. It could be that a long - lost spellbook is found, and the characters start to experiment with spells that are more powerful and dangerous than what they are used to. This could lead to all sorts of situations, from accidentally creating new magical disasters to using these spells to fight off new, unexpected enemies.
One interesting plotline could be Voldemort being redeemed. It's a really different take as in the original books he's pure evil. But in fanfic, some writers explore what if he had a change of heart.