No. The Powerpuff Girls are known for their heroic deeds and strong characters. Fanfic that involves diapers in relation to them is inappropriate as it distorts their intended image.
It could be a fan - created story related to the Powerpuff Girls in a brick - like or building block - inspired world. Maybe it features the Powerpuff Girls having adventures in a world made of bricks, with new villains and challenges.
One great fanfic is 'The Unlikely Alliance'. It explores a scenario where the Powerpuff Girls and the Rowdyruff Boys have to team up to face a new super - villain in Townsville. It's full of action and some really interesting character interactions.
The Powerpuff Girls Z themselves - Blossom, Bubbles, and Buttercup are often very popular. Fans love to write about their different personalities and how they interact with each other. For example, Blossom's leadership, Bubbles' kindness, and Buttercup's tough - girl attitude. Also, the villains like Mojo Jojo can be popular. His devious plans and his rivalry with the girls make for interesting stories in fanfic.
One interesting storyline could be the Powerpuff Girls Z facing a new, super - powerful villain from another dimension. This villain has powers that are the opposite of theirs and can manipulate time, causing chaos in Townsville. Another could be a story where they lose their powers temporarily and have to rely on their wits and teamwork to save the day. Maybe they team up with some of their former enemies who also realize the new threat is too great for them to handle alone.
I'm not sure there are really 'interesting' aspects in this as it might seem a bit of an odd or inappropriate concept. The Powerpuff Girls are meant to be strong, independent superheroes, and focusing on such a strange idea like 'diaper fanfic' goes against their original positive and empowering image.
Another theme could be the exploration of the characters' powers. In fanfic, authors often play around with how the girls' and boys' powers interact and develop. For example, they might create scenarios where the Powerpuff Girls Z have to use their powers in new ways to defeat the Rowdyruff Boys when their powers are enhanced. There can also be stories about the origin of their powers being different from what is shown in the original series. This can lead to very interesting plotlines. And sometimes, there are themes related to teamwork. Even though they are often on opposite sides, some fanfics explore the idea of them having to work together for a common goal.
One idea could be an OC who has a unique power like the ability to control plants. She could team up with the Powerpuff Girls to stop Mojo Jojo from creating a giant plant monster to take over Townsville. Another plot could involve an OC from another dimension who comes to Townsville seeking help because her own world is being threatened by a similar evil as in Townsville. The OC could bring new powers and a different perspective to the fight against the villains.
I'm sorry I can't recommend specific 'powerpuff girls brick fanfic' as I don't have a list of them at hand. But you can try searching on fanfic websites like Archive of Our Own or FanFiction.net.