Well, Naruto has a big heart. So he would surely be very kind to the abandoned baby. He might introduce the baby to his friends like Sakura and Sasuke. They could all help in taking care of the baby. The baby could also grow up to be a great ninja, inspired by Naruto's story and his teachings.
Perhaps Naruto would first search for the baby's parents. He'd ask around the village, using his connections. Along the way, he'd protect the baby from any harm that might come its way. And the baby could become a symbol of hope for the village, like Naruto himself once was.
In this fanfiction, Naruto might take the baby in and raise it as his own. He could teach the baby ninjutsu skills he has learned over the years. Maybe the baby has some special powers that are gradually discovered as the story progresses.
The baby could turn out to have some sort of special chakra. Naruto, being curious and always wanting to help, tries to find out more about it. He might seek help from Kakashi or other experienced ninjas.
Well, Naruto might try to protect the baby dragon from any harm. He could use his ninja skills to keep it safe from enemies who might want to capture it for its power or rarity.
Well, if Naruto found Mjolnir in a fanfiction, he might initially be really confused. I mean, Mjolnir is from a completely different fictional universe. He'd probably try to lift it out of curiosity. Given Naruto's determination and pure heart, there's a chance he could actually lift it. And if he did, he'd gain the power of Thor, which would be really cool to see combined with his ninja abilities.
Well, if Naruto finds a gun in a fanfiction, it would be really out of place in the ninja world he's from. But he might be confused at first. He'd probably try to figure out what this strange object is, since it's so different from his shurikens and kunai. He might even accidentally set it off, causing chaos in the village.
In such a fanfiction, Naruto might become a rogue ninja. He could be filled with anger and resentment towards his former team. Maybe he'd seek power elsewhere, perhaps from villains who would take advantage of his vulnerable state.
In fanfiction, if Harry Potter finds a baby phoenix, it could be a very magical encounter. The baby phoenix might be in need of protection. Harry, being the hero he is, would likely take it under his wing. He could use his knowledge of magical creatures from Hogwarts to care for it. Maybe the phoenix would grow up to be a powerful ally for Harry in his future adventures.
Another way the story could go is that the baby has a unique ability that attracts the attention of other villages. Naruto then has to protect the baby from those who might want to use its power for bad. He could train the baby to control its power and also form alliances with other villages to ensure the baby's safety. Along the way, the baby could learn about Naruto's own past and be inspired to become a strong and kind ninja like him.
Well, Naruto might take the baby wolf to his home in the village. He could raise it as his own, teaching it ninja skills when it grows up. Maybe the wolf would become his loyal companion, like how Akamaru is to Kiba.
Well, Naruto finding a baby boy in a fanfiction could lead to all sorts of adventures. Maybe the baby has some special power or is a key to some mystery in the Naruto world. Naruto would then have to protect the baby from those who would want to use the baby's power for evil.
He could decide to protect the baby girl himself. Naruto has a big heart. He might see the baby as someone he needs to look after, just like how he was always looking out for his friends. Maybe he starts teaching her some basic ninja skills when she grows a bit older.