Another idea is that the Smash Bros characters are transported to the Naruto universe. They'd have to adapt to the ninja world. For example, Mario might try to use his jumping skills on the rooftops of Konoha, while Link could use his swordsmanship against ninja foes. It would be really interesting to see how they interact with the Naruto characters and learn about chakra.
A third plot could involve a new villain that threatens both universes. Naruto and some of the Smash Bros characters team up to fight this villain. They'd have to combine their unique abilities. Naruto's ability to sense danger with his ninja senses and the Smash Bros characters' various powers like Kirby's inhaling ability or Samus's blaster skills would make for an epic battle.
Well, a really engaging plot point often involves Naruto bringing his unique ninja techniques into the Smash Bros arena. For instance, his ability to use chakra in a world full of characters with different power sources. Also, the idea of Naruto trying to understand the Smash Bros power - ups and how they can enhance his abilities or those of his newfound allies. And then there's the whole concept of Naruto facing off against characters with completely different moral compasses than his own, like some of the more villainous Smash Bros characters.
A plot could revolve around a new character being added to the roster secretly. This character has an unknown power that starts to disrupt the balance in the Smash Bros world, and the other characters must figure out who it is and stop them. For example, this new character could be causing glitches in the battle arenas, making it difficult for the regular characters to fight.
Well, you could have a story where a new villain emerges in the combined Naruto - Super Smash Bros world. This villain has the power to steal the abilities of the characters. Naruto and his comrades, along with the Smash Bros characters, have to team up to stop this villain. They go on a journey across different stages of the Smash Bros game to find the source of the villain's power and defeat him. Along the way, there are many battles, character development, and some humorous moments as the two different groups of characters interact.
One idea could be a crossover with a classic RPG like Final Fantasy. Characters from Final Fantasy could enter the Super Smash Bros universe and bring their unique abilities. For example, Cloud could use his Omnislash. Another idea is a crossover with an anime like Naruto. Naruto characters would add a whole new dynamic with their ninja skills. And a third idea could be a crossover with a horror game, like Resident Evil. The spooky elements and unique weapons of Resident Evil characters would make for a very different kind of Super Smash Bros fanfic.
Naruto and Kirby would be really interesting. Kirby could copy Naruto's abilities, like his running speed or his ability to use chakra. And Naruto could be amazed at Kirby's cuteness and his unique way of fighting, like inhaling enemies. They could have a really fun dynamic together.
One idea could be a story where all the characters from different universes team up to face a new, unknown threat that is causing glitches in their worlds. For example, Mario, Link, and Pikachu working together in a way they never have before.
One idea could be an OC from a relatively unknown game getting invited to the Smash Bros universe. They have to learn the ropes of the unique fighting style there. Another could be an OC who has a special power that disrupts the balance in the Smash Bros world, causing both chaos and new alliances among the characters.
One idea could be a crossover within the Smash Bros universe. For example, characters from Star Allies team up with unlikely allies in the Smash Bros world to face a new, powerful threat that combines elements from both games. Maybe a villain who can manipulate the power - ups and stages in a strange way.
One idea could be an OC from a little - known game series getting invited to the Smash Bros world. They could start off as an underdog, struggling to adapt to the intense battles and different fighting styles. But as the story progresses, they learn from the veteran Smash characters and develop their own unique combat techniques, eventually becoming a respected fighter in the Smash universe.
An interesting plot for a Super Smash Bros Brawl OC fanfiction could involve an OC that is a master of disguise. This OC can transform into any of the existing Smash Bros characters, but with a twist. Their abilities are a bit different from the original characters. They use this power to create chaos during battles, making other characters suspect each other. As the story progresses, they start to have a change of heart and end up using their power for good, helping the Smash Bros community deal with an outside threat that none of the regular characters can handle alone.