The baby could be an alien species that Goku has never encountered before. It might have special powers related to its alien origin, like the ability to control energy in a different way than Goku and his friends.
The plot might involve Goku finding the baby as part of some sort of mystery. For example, the baby could be a key to unlocking a hidden power or an important prophecy. Goku, being the hero he is, decides to protect the baby at all costs. He may seek help from his friends like Bulma to figure out more about the baby and its significance.
The baby could be an ordinary human baby that has some sort of latent magical ability that Raven senses. She then decides to protect the baby from the human world that may not understand or accept the baby's potential magic, and also from the magical world that might want to exploit the baby.
The baby could be an orphan from a nearby village that has been attacked. Kagome stumbles upon the baby while on her travels with Inuyasha. Since she has a big heart, she can't just leave the baby there, so she takes it with her.
The baby could be a lost elf child from a different part of the forest. Maybe their family was attacked by some dark force and Thranduil finds them by chance.
The baby could be a half - demon, related to some other important character in the series. Maybe it's the offspring of a character Sesshomaru has some history with.
In this fanfiction, aside from Gohan, there could be other characters. For instance, Piccolo. Piccolo might sense Goku's power and be both intrigued and a bit wary. He could approach baby Goku to either assess the threat or try to understand his power source. Also, Chi - Chi might be involved. Even as a child herself, she could be drawn to Goku because of his unique presence and power, which could start their early relationship in a different way compared to the original story.
One great fanfiction where Stiles finds a baby could be 'Stiles' Unexpected Bundle'. In this story, Stiles discovers a baby on his doorstep and has to figure out what to do while also dealing with the chaos in his supernatural - filled life. It's a heart - warming read that shows Stiles' kind and responsible side.
One idea could be that the baby is from a hidden clan. Naruto decides to protect the baby from those who would use its special abilities. He takes the baby under his wing and trains it as it grows up, passing on his ninja values.
A lesser - known 'Inuyasha finds a baby' fanfiction is set in a different timeline. Inuyasha finds a baby that seems to be from the future. The baby's presence causes a stir in the feudal era as everyone tries to figure out where it came from and what its purpose is. This fanfic is full of mystery and adventure as Inuyasha and his friends try to solve the mystery of the baby.