They could save a group of kittens from a burning building. Lucky uses his speed to run in and find the kittens, while Patch figures out a way to lead them to safety through the smoke.
Maybe there's a big dog - catcher in town who is trying to catch all the stray dogs. Lucky and Patch find out his plan and they manage to outsmart him at every turn. They set up little traps and distractions to keep the dog - catcher busy, and in the end, they become heroes to all the dogs in the neighborhood. They use their unique skills - Lucky's agility and Patch's intelligence - to their advantage throughout this whole ordeal.
They could go on a journey to find a hidden treasure in the city. Maybe they discover an old map in an alley and follow it, facing various challenges like mean cats and big puddles along the way.
Pongo and Perdita, as the parents of the dalmatians, would surely interact with Patch. They could offer him advice, scold him when he's misbehaving, or be proud of him when he does something good.
Maybe Patch discovers a hidden talent for something like painting or dancing. The other dalmatians are initially skeptical but then come to support him. This could involve some fun interactions and a bit of a self - discovery journey for Patch.
Obviously, Lucky is one of the main characters. He's often the focus as the story is centered around him.
One interesting fanfiction could be about Lucky's adventures on his own away from the other Dalmatians. Maybe he stumbles upon a magical place in the forest that only he can see.
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 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.
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.
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 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.