In this type of fanfiction, the plot can get really creative. Maybe the kidnappers use some sort of new technology to keep the kidnapped Overwatch character subdued. For example, they could use a device that dampens the powers of a hero like Winston. The other heroes would then have to find a way to counter this technology while also rescuing their comrade. Fanfictions like these often play on the existing relationships between the Overwatch characters and add a new layer of drama and adventure.
First, choose the character to be kidnapped. It should be someone whose absence will create a big impact, like Soldier: 76 or Pharah. Then, decide who the kidnappers are. It could be a new villain or an existing group like Null Sector. Outline the plot including how the kidnapping takes place and the initial reactions of the other characters.
One example could be a fanfiction where a mysterious guy kidnaps a character from a popular TV show. For instance, in a fanfic based on a superhero series, a villainous guy might kidnap the superhero's sidekick to lure the hero into a trap. This creates a lot of drama and tension in the story as the hero then has to figure out how to rescue their friend.
There could be a fanfiction where Evie is kidnapped by an obsessed fan within the story. This fan might be envious of her beauty and charm and wants to keep her all to themselves, leading to a rescue mission by her friends from the 'Descendants' world.
One good example could be those that explore Bastion's discovery of the world beyond combat. They might focus on his interactions with nature, like when he encounters a lemon tree. The author could describe how Bastion is intrigued by the lemons, their smell and texture, and how this simple encounter changes his view of the world a little bit. This kind of fanfiction can add depth to Bastion's character in a rather unique way.
One good example could be a story where the Thundercats are kidnapped by an unknown alien race. The writer might focus on how the Thundercats use their unique skills and teamwork to escape. For instance, Lion - O could use his Sword of Omens to find a way out while the others distract their captors.
There might be a fanfic where Merlin is kidnapped by a neighboring kingdom that wants to use his knowledge of Camelot's secrets. This could lead to a story full of political intrigue as Camelot tries to negotiate his release while also preparing for a possible war if negotiations fail. The fanfic could explore Merlin's own struggle to escape while being held captive.
One example could be a story where Rey is kidnapped by a group of smugglers who think she has valuable information about hidden Jedi artifacts. They hold her captive on a remote planet, but Rey uses her Force skills to gradually turn some of the captors to her side.
One great example could be 'The Rescue in the Stars'. In this fanfiction, the reader is kidnapped by a Sith Lord and the heroes of Star Wars have to embark on a dangerous mission to save them. It has great action scenes and stays true to the Star Wars universe in terms of the characters' personalities and the use of the Force.
I'm afraid I can't provide exact examples of 'flash kidnapped fanfiction'. However, generally in fanfiction, if Flash is a character like the Flash from DC Comics, an example might be a story where the Flash is kidnapped by a powerful villain who wants to steal his speed. The story could then follow the other Justice League members trying to find and rescue him.
Sorry, I haven't come across any specific examples of 'that kitten kidnapped fanfiction' as it seems like a rather unusual and specific concept.