In Naruto x Starlight fanfiction, a cool idea could be the sharing of abilities. Maybe the characters from Starlight learn about chakra and start to develop their own forms of it. This could create a whole new dynamic in the story, with both sides learning from each other.
One interesting concept could be the unique world - building. Maybe it has a steampunk - like setting with clockwork mechanisms everywhere, from the city's infrastructure to the characters' gadgets. This can create a really immersive and visually appealing environment.
One interesting concept could be the way Naruto's ninja skills are translated into 'gamer' abilities. For example, his shadow clone jutsu might be like a skill in a game that he can level up to create more clones or make them stronger. It's a cool mash - up of the Naruto universe and typical gamer elements.
Another concept might be Naruto characters in the political intrigue of Westeros. For example, Naruto himself could be inserted into the story during a time of great conflict in the Seven Kingdoms. His ability to make friends and influence people could change the power dynamics in a completely different way compared to the original ASOIAF characters.
Character relationships are also a big part. Maybe Naruto and Korra become friends and mentors to each other. Naruto could teach Korra about his experiences with inner demons and self - improvement, while Korra could show Naruto new ways of looking at the world in terms of elemental balance.
Well, in Naruto x Nebula fanfiction, a cool idea might be that the chakra system in Naruto has some connection to the energy within a Nebula. Maybe the Sage of Six Paths' power was somehow influenced by Nebula energy in the past. Also, there could be a story where Naruto and his friends have to protect the Ninja World from a threat that comes from a Nebula, like an alien race with powers based on Nebula forces.
One interesting concept could be the characters from Naruto using Yugioh cards in their battles. For example, Naruto might use a card that represents his Rasengan to gain an advantage in a fight. Another concept could be the crossovers of the different power systems. The chakra in Naruto and the magic in Yugioh could be combined in unique ways in fanfiction.
One interesting concept could be a Naruto crossover with the world of Harry Potter. Imagine Naruto characters learning magic spells at Hogwarts. Another concept might be a crossover with the Avatar: The Last Airbender universe, where Naruto characters interact with benders and learn about the four elements in a different way. There could also be a crossover with the Bleach universe, with Naruto characters facing off against Hollows and Soul Reapers.
One interesting concept could be the combination of Naruto's ninja abilities with Undertale's unique battle system. For example, Naruto's shadow clones might interact in a strange way with the bullet - hell - like attacks in Undertale. Another concept could be the characters from both universes meeting and forming unexpected relationships. Naruto's friends could meet Sans or Papyrus from Undertale and have to learn to communicate across their very different cultures.
In RWBY x Naruto fanfiction, a cool concept is the crossover of character relationships. For instance, Ruby could befriend Naruto due to their similar positive outlooks and determination. Weiss might have an interesting dynamic with Sasuke as they both come from noble families and have a certain pride. Also, the idea of RWBY's world being opened up to the idea of ninja training academies and Naruto's world getting to know about Dust - based technology would make for some really engaging stories.
Perhaps the story explores how the order and precision of clockwork mechanisms interact with the chaotic and often unpredictable nature of the Naruto universe. This could create some really cool plotlines, like a villain using clockwork - based jutsu to try and control the flow of battles in a very methodical way.