In certain fanfictions of this kind, the plot might involve Draco's ferret form being used by his enemies to embarrass him further. However, this could also lead to a character arc where he learns humility. There could also be a story where his transformation is related to a prophecy. As a ferret, he has to go through various adventures to fulfill the prophecy's requirements, all while dealing with the challenges of being a small, furry creature in a world of wizards and witches.
Well, in some 'Draco turned into a ferret fanfiction', there could be a plot where Draco in ferret form discovers new things about the Hogwarts grounds that he never noticed as a human. Maybe he stumbles upon a secret passage or a hidden magical creature. Also, there could be a story where his transformation is a result of a misfired spell by a student, and the whole school has to figure out how to reverse it.
Perhaps there's a plotline where the transformation into a ferret has some unforeseen side effects. For example, Harry might gain some ferret - like abilities such as enhanced sense of smell or speed, which he then uses to his advantage in solving a mystery or escaping from a dangerous situation in Hogwarts. He could also struggle with some of the more ferret - like instincts, like being tempted to hoard shiny objects.
Obviously, Draco Malfoy is the central character since he's the one who turns into a ferret. Harry Potter often appears as well, as he has a history of conflict with Draco. Hermione Granger might also be there, perhaps using her knowledge to try and figure out a way to turn Draco back. Ron Weasley could be included too, probably making some snide remarks about Draco's new form.
One interesting plotline could be that Harry discovers Draco in his ferret form injured in the Forbidden Forest. He decides to take care of him secretly in his dormitory. As he nurses Draco back to health, they start to understand each other better, breaking down the long - held grudges between them.
One possible plotline could be Naruto having to adapt to his new fox form and learning how to use its unique abilities. For example, he might discover that in fox form he has enhanced speed and stealth, and he has to figure out how to incorporate these into his fighting style.
Another plotline could involve Sookie using her new vampire powers to solve mysteries in the supernatural world. Since she already had some unique abilities as a human, becoming a vampire could enhance them and make her a sort of detective in the vampire community.
A more adventurous plotline could be Eragon as a dragon getting involved in battles on a much larger scale. He could use his new form to take on powerful enemies that were previously too difficult for him as a human. His dragon form might also attract the attention of other mythical creatures, leading to new alliances or rivalries.
Another plotline could involve Megatron using his knowledge from being a Transformer in his new human form. Maybe he uses his strategic skills to solve human problems, like helping in a corporate takeover in a more ethical way than the humans were planning.
A third plotline could be Draco's struggle with his identity. He has the memories of his previous life, but he's now in Draco's body. He has to deal with Draco's family expectations, his reputation at Hogwarts, and at the same time, he wants to do things differently. This internal conflict could lead to a lot of character development and new story arcs.
One interesting plotline could be that they discover their twin relationship early on and try to keep it a secret from everyone at Hogwarts. They might secretly help each other out in classes and with their rivalries against other houses.
One interesting plotline could be Draco trying to adapt to Muggle technology. For example, he might struggle with using a mobile phone at first, which could lead to some comical situations as he accidentally calls the wrong people or activates functions he doesn't understand. Another plotline could be his interaction with Muggle schools. He might be shocked by the different teaching methods and lack of magic in the curriculum. Also, a potential plotline could involve Draco making Muggle friends and learning about their values, which could be a huge contrast to what he's used to in the wizarding world.