In this kind of fanfiction, there could be a crossover where the Pokemon world's healing techniques are combined with Naruto's medical ninjutsu. Since there's the 'immortal' aspect, perhaps an elixir from the Pokemon world that grants immortality is sought after in the Naruto world. Also, the different regions in the Pokemon world could be like hidden villages in Naruto. Trainers from the Pokemon world could come to the Naruto world to learn about chakra, and Naruto characters could go to the Pokemon world to understand their unique powers.
In Naruto Pokemon God fanfiction, the idea of the Pokemon world's gods having an impact on the Naruto world is very popular. For instance, the god of Pokemon like Dialga could manipulate time in the Naruto universe. Or Giratina could be involved in the darker aspects of the Naruto world, like the Orochimaru - like experiments. And many fanfictions explore how the Pokemon themselves would adapt to the chakra - based environment of the Naruto world.
A really interesting crossover is when the Fruits Basket characters' zodiac animals are related to specific Pokemon types. For example, the rat character could be associated with a Pikachu - like electric type Pokemon. It creates a whole new dynamic.
One interesting crossover could be Ash and his Pokemon traveling to the Naruto universe and having to deal with the ninja world's challenges. Maybe Pikachu uses its electric attacks against ninja techniques.
One interesting crossover could be the characters from Naruto using Pokemon moves in a battle. For example, Naruto could use Pikachu's Thunderbolt move in his own unique way. Another could be the Pokemon existing in the Naruto world and being used by shinobi for various missions. They might be used for scouting, like a Pidgeot flying over enemy territory, or for combat support, such as a Charizard breathing fire to fend off attackers.
In some fanfictions, they might explore how Ash's bond with his Pokémon is similar to Naruto's bond with his friends in the Hidden Leaf Village. Ash's journey to become a Pokémon master and Naruto's journey to become Hokage both involve growth, friendship, and facing challenges. They could learn from each other's experiences. For instance, Naruto could teach Ash some of his ninja stealth techniques which could be useful when catching Pokémon in the wild.
One interesting crossover could be Naruto having to team up with a Legendary Pokemon like Mewtwo. Imagine Naruto's speed and combat skills combined with Mewtwo's psychic powers. They could face off against powerful villains from both the Naruto and Pokemon universes. Another could be a story where Naruto discovers a Legendary Pokemon egg and has to protect it while on a mission.
A really interesting crossover is when Naruto's chakra system is integrated into the Freezing world's combat system. It makes for some really intense battles. For instance, Naruto might use his Rasengan while the Freezing characters use their Pandora powers, creating a whole new dynamic.
The concept of bringing the Sharingan or other unique Naruto abilities into the SWTOR world is also quite interesting. In some fanfictions, a character with the Sharingan has an edge in the SWTOR universe, being able to predict the movements of enemies in lightsaber duels or understand the motives of Sith and Jedi more easily. This crossover really plays with the idea of how different power systems can interact and give certain characters an unexpected advantage.
One of the most captivating crossovers is where the characters from Hellsing are inserted into the Naruto world during a time of great unrest. Alucard's overpowered abilities create a whole new dynamic in the ninja world. The shinobi have to figure out how to deal with a being that is almost indestructible. And Naruto, with his never - give - up attitude, tries to understand and maybe even befriend Alucard. This crossover plays with the concepts of power, friendship, and good vs. evil from both universes.
The crossover where Naruto and Beelzebub characters team up to fight a common enemy is quite interesting. It allows for a great display of both the ninja abilities from Naruto's world and the unique powers in Beelzebub's world.