In a fanfiction, Waddlesworth and Oddball could be the heroes of the Dalmatians. When the group of Dalmatians is in trouble, perhaps facing a new villain who wants to capture them all. Waddlesworth, with his cleverness, and Oddball, with her unique skills (maybe she can do something extraordinary because of her different genes), they team up to outwit the villain and save their Dalmatian family.
One plot idea could be Waddlesworth getting lost in the big city and having to find his way back to the Dalmatians. He could encounter various other animals along the way, some friendly and some not so much, which would make for an exciting adventure.
You can try looking on fanfiction websites like FanFiction.net or Archive of Our Own. They have a wide variety of fanfictions. Just search for '102 Dalmatians Waddlesworth' in their search bars, and you might find some great stories.
A plotline could be that Waddlesworth and Oddball get separated from the rest of the Dalmatians during a journey. They then have to rely on each other to survive in the wild. They face various challenges like finding food and shelter, and along the way, they grow closer as friends.
For character development, you could focus on the 102nd Dalmatian being an outcast at first. Maybe it has a different - colored spot or a unique behavior that makes the other Dalmatians hesitant to accept it. But as the story progresses, it shows great courage and loyalty, winning the others over.
One possible plot could be that the Dalmatians discover a hidden talent among them, like the ability to communicate with other animals in a special way. They use this talent to save their neighborhood from a new threat, perhaps a developer who wants to destroy their park.
One idea could be that Pongo and Perdita discover a hidden talent in one of their puppies. For example, one of the puppies has an amazing ability to find lost things. So, they start using this talent to help the neighborhood. They become local heroes as they find lost toys, keys, and even small pets. It brings a lot of joy to the community, and Pongo and Perdita are very proud parents.
A third idea is to set the fanfiction in a modern-day scenario where the Dalmatians become famous on social media. The 102 Dalmatians have their own Instagram account and attract the attention of a big Hollywood producer. But there are also some jealous animals who try to sabotage their new - found fame.
One idea could be that the jewel is a magical heirloom of the Dalmatian family. It has the power to protect them from the evil Cruella. The puppies go on an adventure to find the jewel when they sense Cruella's return.
One common theme is self - discovery. Since Cadpig is a young and small dalmatian, many fanfictions focus on her finding out her own strengths and weaknesses. For example, she might discover that she's braver than she thought when faced with a bully.