Another interesting angle for a 'Paper Mario Sticker Star' fanfic would be to focus on the backstories of the existing characters. For example, you could explore the origin of Bowser's obsession with the Sticker Comet. Maybe there was a childhood event that made him covet it so much. This could add depth to his character and also create a more engaging story as you tie in his past with the events of the game world.
One idea could be to create an alternate universe where the stickers have minds of their own and they form a rebellion against the characters who use them. It would add a whole new layer of conflict and adventure.
Well, you could write a fanfiction where Mario gets trapped in a world made entirely of stickers. He has to find a way to break free by solving various puzzles using only the stickers he can find. Or perhaps a story about a villain who is stealing all the rare and powerful stickers, and Mario has to stop him while also learning about the villain's backstory which led to this evil plan.
You could write a Paper Mario fanfic that involves time travel. Mario goes back in time to prevent a great disaster that happened in the past of the Paper Mario world. This could lead to him interacting with past versions of characters and changing the course of history in unexpected ways. Or, a fanfic about a new villain that only exists in the paper realm and has unique powers that Mario has to figure out how to defeat.
The boss in the haunted mansion has a very memorable story. It's all spooky and mysterious, which adds to the overall atmosphere of that part of the game.
Well, in Paper Mario Sticker Star, the boss stories vary greatly. Some bosses are guardians of certain areas. Take the boss in the desert area, for instance. It might be protecting a precious sticker or an important location. The bosses' stories are often intertwined with the overall plot of the game. They present challenges that Mario has to overcome, and as you progress through the game, you learn more about why these bosses exist and what their motives are. It adds depth to the gameplay experience.
Well, you could focus on unique character interactions. Instead of the usual pairings, create new alliances or rivalries among the characters. For example, make a story where a minor enemy from the game teams up with Mario for a common goal.
One underrated character is the Big Buzzy Beetle. In fanfiction, we could see a story where this character is actually a guardian of an ancient sticker relic. He's been misunderstood all this time. Also, the Shy Guys. They're quite common in the game but not really explored deeply. A fanfiction could be about a group of Shy Guys who have a secret society within the Sticker Star world and Mario stumbles upon their plans, which could be either good or bad depending on how you write it.
One idea could be a crossover with the Mario Kart universe. Mario and his friends from Super Paper Mario could find themselves on the race tracks, facing off against the regular Mario Kart characters. Another could be a crossover with the Legend of Zelda. Maybe Mario has to traverse Hyrule, using his paper - like abilities in a new and strange land filled with Zelda - style dungeons and puzzles.
Another interesting concept is that the harem is formed due to a magical accident. Mario has to figure out how to reverse it, but in the process, he discovers that each member of the harem has a hidden power or ability. So instead of just trying to get rid of the situation right away, he decides to work with them to solve a greater threat to the Paper Mario world. The fanfiction could then detail their journey and the growth of their relationships.
One idea could be that Naruto gets transported to the Mario world. He might use his ninja skills to help Mario and Luigi in their battles against Bowser. For example, Naruto could use his Shadow Clone Jutsu to confuse Bowser's minions while Mario goes for the power - up.
One idea could be a racing tournament where Mario and Sonic team up against some new, powerful villains. They have to combine their unique skills, like Mario's jumping and Sonic's speed, to overcome the challenges of the track which is filled with traps from both of their worlds.