One common way for Marinette to get revenge in fanfiction could be through her fashion skills. She could design something that makes Lila look foolish. Like creating a dress for an event that has a hidden message or design that mocks Lila's lies when she wears it. It's a more creative and less confrontational way of getting revenge, but still very effective in showing Lila that Marinette is not one to be trifled with.
One story could be that the husband found out his wife was cheating. Instead of getting violent, he quietly gathered evidence. Then he exposed her affair to their families and friends, which led to her being ostracized in their social circle.
It could be a rogue ninja who has a personal vendetta against Boruto's family. This ninja might have caused harm to Boruto's father Naruto in the past, and now Boruto is determined to make him pay.
Perhaps the target is Howard. Howard might have made a joke about Sheldon's mother that Sheldon didn't appreciate. As a result, Sheldon could try to get revenge by interfering with Howard's work on the space station projects, causing minor but annoying setbacks.
One idea could be to team up with her friends. They could all surround the person who tickled her feet and start tickling him or her from all sides at once. This would be a kind of group revenge and would surely make the person regret tickling her feet.
One common theme is justice. Naruto seeking revenge is often seen as a way to right the wrongs done to him or his loved ones. It's about making the guilty pay for their actions.
Betrayal is a common theme. Usually, something or someone has wronged Harry deeply, which sets him on the path of revenge. For example, it could be the Ministry of Magic turning against him or a supposed friend revealing his secrets.
Once there was a girl named Lily. Her brother used to constantly tickle - torture her. One day, she had enough. She found out that her brother was extremely afraid of spiders. So, she bought some fake spiders and put them in his bed. When he saw them, he screamed and was really scared. Lily finally got her revenge in a rather harmless but effective way.
Well, maybe Boruto's family or friends are hurt by a powerful enemy. So he decides to train hard and seek revenge. He might travel to different places to learn new jutsu and gather allies along the way.
It could be about Sheldon getting back at someone who wronged him in the series. Maybe it's Leonard who ate his last slice of pizza without permission, so Sheldon devises an elaborate plan to make Leonard's life a little chaotic for a while.