There could be a theme of mentorship. Yamato could be learning from Kakashi's vast experience, or vice versa. They might also have a theme of trust, where they have to trust each other completely in a dangerous situation, like being trapped in an enemy's jutsu. This can show how their relationship is based on mutual understanding and faith in one another's abilities.
A theme could be their shared experiences in the Hidden Leaf Village. Maybe they recall a particular event from their past that strengthened their bond. Also, their loyalty to the village and how they protect it together can be a great theme. This can include them going on missions to safeguard the village from external threats and relying on each other's skills in the process.
One possible theme could be their deep friendship. They could be shown supporting each other through tough times, like when facing a powerful enemy. Another theme might be their growth as ninjas. For example, they could train together and learn new techniques from each other.
One possible theme could be their friendship. Vivi was an important part of the Straw Hat crew's journey in the Alabasta arc. Fanfictions could focus on how they became friends, like how Luffy's simple - minded but kind nature won Vivi over, and how they supported each other during battles and difficult situations.
One possible theme could be mentorship. Kushina could be portrayed as a mentor to Sakura, guiding her in areas like dealing with strong - willed men, given Kushina's relationship with Minato. Another theme might be friendship. They could bond over their shared experiences of being in a world full of powerful shinobi.
One possible theme could be a comical take on Batman in a baby - like or vulnerable state. It might be about how the other characters in the Batman universe react to this strange situation.
One possible theme could be about Rapunzel's journey into motherhood and how she overcomes her fears. For instance, she might be worried about being a good mother since she was locked away for so long and didn't have a normal upbringing herself.
One possible plotline could be them going on a journey together. They might start off bickering like they often do, but as they face challenges on the road, they gradually become closer friends. For example, they could be searching for a rare ingredient for a medical experiment Karin is doing, and along the way, Suigetsu protects Karin from various threats.
One possible plotline could be that Naruto discovers a new type of bathhouse in the Hidden Leaf Village that uses lemon - scented oils for relaxation. He tries it out and has a series of comical interactions with the other villagers who are also there. Maybe he accidentally slips on a lemon - scented soap and his friends have to help him up, all while sharing some light - hearted banter.
Another theme could be the power dynamic. Naruto has his powerful chakra and Katara has her waterbending skills. How they combine their powers or learn from each other's abilities can be a great theme. They might also face challenges together and grow as characters through these experiences.
One possible plot could be that Orochimaru, instead of being completely evil, has some sort of redemption arc that involves Sakura. Maybe Sakura is the one who tries to understand Orochimaru's past and the reasons behind his actions. They could form an unlikely alliance where Sakura tries to teach Orochimaru about the value of life and friendship, and in the process, they develop a mutual respect for each other.
One possible plotline could be that the Crystal Gems are captured by a new and powerful enemy. They have to use their wits and the unique abilities of each gem to find a way to escape. For example, Garnet might use her future vision to anticipate the enemy's moves, Pearl could use her combat skills and knowledge, and Amethyst her shape - shifting abilities in unexpected ways.
One possible theme could be their relationship as two extremely powerful Pokémon. They might start as rivals, each thinking they are the more powerful or important being in the Pokémon world, and then gradually develop a mutual respect through various encounters and battles.