One common storyline is the 'recovery arc'. Tails is sick with a chest cold, and the story focuses on his journey to getting better. His friends support him throughout, and there are heartwarming moments as they help him through the tough times.
There could also be a 'role - reversal' type of storyline. Usually, Tails is the one helping others with his inventions and smarts. But when he has a chest cold, the others have to use their own skills to take care of him. It shows a different side of the relationships between the characters.
Another storyline could be a 'mystery illness' angle. At first, everyone thinks it's just a normal chest cold, but as the fanfiction progresses, it turns out to be something more serious or related to some external factor like a new enemy's weapon. This adds an element of suspense.
The chest cold can also be described in a more detailed way in fanfiction. Writers might talk about the symptoms like a tight feeling in his chest, shortness of breath, and how he tries different remedies. Some fanfictions might even have Tails trying out some wacky or home - made cures while his friends watch with a mix of concern and amusement.
One common plotline could be Naruto trying to hide his chest cold from his friends while on a mission. He doesn't want to seem weak or hold the team back. Another could be his friends noticing something is off and trying to figure out what's wrong with him. They might suspect it's a more serious condition at first.
One common storyline is the rivalry over Ash. Since both Serena and Miette seem to have an interest in Ash, they might compete in different ways. Another storyline could be about their growth as Pokemon trainers. They may start off at different levels and through their interactions, they both improve. Also, there could be a storyline where they have to work together against a common enemy in the Pokemon world, despite their differences.
A common storyline is Jade being a new student at Hogwarts who quickly becomes friends with the main characters. She might have some sort of special talent that helps them solve a mystery or face a new threat. For instance, she could be an expert in ancient runes and use that knowledge to decipher a hidden message that leads to an important discovery.
One common storyline is Persephone being a key figure in a quest. For instance, Percy and his friends might need to seek her help to gain access to a certain part of the Underworld. Another is her involvement in power struggles. Maybe there's a conflict between the gods and she has to choose a side, and this choice affects the demigods. For example, if there's a fight between the Olympians and the Titans again, her loyalty could be a major factor.
One common storyline is that McGonagall has to protect Hogwarts from a dragon that has been magically lured to the school. She uses her Transfiguration skills to create barriers or even to transform objects to fend off the dragon.
A lot of fanfiction involves Ares trying to corrupt Percy or his friends. He could offer them power in exchange for their loyalty, tempting them to turn away from their good - natured ways. It's also common to see storylines where Ares has some sort of vendetta against a particular character, like Annabeth, and he tries to get back at them through various devious means.
One common storyline is Krissy getting into trouble during a hunt and Dean coming to her rescue. Another could be them working together to take down a powerful supernatural being.
One common storyline is the family drama within the Black family. Since Bellatrix is a Death Eater, Narcissa's loyalty to her family and the dark side, and Andromeda's break from the family traditions, there are often conflicts. Another storyline is how they interact with other major characters. For example, Bellatrix's encounters with Harry Potter. Also, some fanfictions explore Narcissa's role in protecting Draco during the war, which can be related to the actions and influence of her sisters.
One common storyline is her struggle to redeem the family name. Since Grindelwald was a dark wizard, she might be on a mission to prove that her family can also be a force for good in the wizarding world. This could involve her doing heroic deeds and showing that she is not like her infamous ancestor.