In some fanfictions, Lucy pranks Erza by making her think that there's a new rule in the guild about eating only sweet things. Erza, being strict about rules, starts to enforce it until she realizes it was a prank. It's memorable because of Erza's initial seriousness.
One idea could be that Lucy pranks Natsu by using her Celestial Spirits to create fake fire-breathing dragons all around the guild. Natsu gets excited at first, thinking there are real dragons, and tries to fight them. When he realizes it's a prank, he's both annoyed and impressed by Lucy's creativity.
Well, there's a fanfic where they prank Carlisle by making his office look like a disco. They put up disco balls, flashing lights and played really loud disco music. It was hilarious. Also, the prank where they switched Rosalie's beauty products for really cheap and smelly ones. Rosalie was so angry and her reaction was quite memorable.
If Lucy never joined Fairy Tail, the friendships and relationships among the characters would form in a very different way. Also, many of the story arcs might not unfold as they do in the original plot.
The power - up trope often occurs in nonhuman Lucy fanfiction. When she becomes nonhuman, she gains new powers. For instance, if she turns into a phoenix - like being, she can rise from the ashes and heal herself. This makes her a more formidable character in the Fairy Tail world and also changes the dynamics of her relationships with other characters as they now have to deal with her new - found strength.
One popular theme is Lucy's growth as a wizard. Fans often explore how she overcomes new challenges and becomes stronger. Another theme is her relationships, not just romantic ones but also her friendships within the guild. For example, her bond with Natsu and how they support each other through tough times.
There are also scenarios where Lucy is targeted because of her celestial spirit magic. Natsu, being aware of the power and danger associated with it, ensures that no one can use Lucy's magic against her or the guild. He'll stand between her and any magic - user who tries to manipulate or harm her because of her unique abilities.
A popular theme is the power - up theme. Lucy might gain new powers related to Demon Slayer abilities in the fanfiction. For instance, she could develop a way to use her magic to purify demons like the Demon Slayers do with their swords.
Well, it would be an interesting concept. Lucy is a very popular character in Fairy Tail. If someone was reborn as her in a fanfiction, they might have to deal with her magic, her relationships with the other guild members like Natsu and Erza. They could potentially change the course of the story, for example, by using modern knowledge to solve problems in the Fairy Tail world more efficiently.
Natsu is probably the most common. Their chemistry in the original series makes it natural for fans to pair them in fanfictions. They have a lot of shared adventures and their personalities complement each other well.
Well, to find a Fairy Tail fanfiction involving Lucy and Froch, start with checking out dedicated Fairy Tail fan communities. These communities often have their own sections for fanfiction. Maybe post a request there asking if anyone knows of such a fic with Lucy and Froch. Another option is to use Google. Type in something like 'Lucy Froch Fairy Tail fanfiction' and look through the search results. Some of the top results might be what you're looking for.