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.
Perhaps they stumble upon a circus that has come to town. They are curious and sneak in. There, they meet all sorts of strange and wonderful animals. They learn some circus tricks from the other animals and even perform a small show for the other dalmatians when they get back home. It's a fun adventure that makes them closer friends.
One possible adventure is that they get lost in the woods. They have to use their wits and sense of smell to find their way back home. Along the journey, they meet friendly squirrels and birds that help them. Lucky's bravery and Patch's cleverness would be key in this adventure. They might also encounter a small stream that they need to cross, which could be a bit scary for them but they manage it in the end.
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 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.
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.
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.
Obviously, Lucky is one of the main characters. He's often the focus as the story is centered around him.
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.
A jealous show - dog breeder could be the new villain. He sees the Dalmatians getting all the attention and decides to plot against them. He tries to frame them for causing chaos at dog shows so that his own dogs can win all the prizes.
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 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.
Perhaps they embark on a journey to find a lost magical creature. Hermione would be excited to study the creature, and Sirius would be there to protect them during the search. Along the way, they might encounter other interesting characters or face challenges that test their friendship and abilities.