There are likely fanfics that explore their relationship in a more platonic sense. Maybe they have to work together to defeat a common enemy or deal with some family drama without any improper content.
One storyline could be that they start a school project together. They might have different ideas at first, but then learn to work together and create an amazing project. It could show their growth as characters and their ability to cooperate.
Phoebe Thunderman is more of the responsible one. She is determined to do the right thing and uphold the family's superhero reputation. She is often the voice of reason when Max gets a little too carried away with his antics.
One great Max Thunderman x Reader fanfiction is 'A Day with Max'. In this story, the reader character gets caught up in one of Max's crazy schemes at school. It's really fun to read as it shows Max's mischievous side while also developing a sweet relationship between him and the reader. Another good one is 'Max's Secret Helper' where the reader accidentally discovers Max's superpowers and they have to work together to keep it a secret from the rest of the Thunderman family.
There should be. Since 'Billy Thunderman' has a wide fan base, including younger viewers, many fans would write stories that are appropriate. These could involve things like Billy's school life, his relationships with his siblings in a positive and clean way, or his attempts to master his powers without any inappropriate content.
Dr. Colosso, the family's pet bunny who is actually a supervillain, is another popular character. Fanfiction might explore his backstory more deeply or have him team up with other villains in a plot to finally defeat the Thunderman family.
One idea could be exploring a time when the Thunderman family loses their powers temporarily and how they deal with normal life. They would have to rely on their wits and non - super skills, which would be a huge change for them.
One popular theme is the development of his superpowers. Writers often explore how Billy further hones his skills and discovers new aspects of his powers.
I'm not sure which specific novel 'Mrs Phoebe' is from. There could be many characters named Phoebe in different novels. Maybe it's a character created by an indie author or a relatively unknown work.