There are usually the main child character, of course. This could be a boy or a girl of various ages. Then there are often parents or guardians, like a mother who is kind and nurturing or a strict father.
Friends play a big role. They can be diverse, some being really outgoing and adventurous, while others are more shy and reserved. Teachers can also be characters. They might be inspiring, like a teacher who encourages the child to pursue their dreams, or they could be a bit of a disciplinarian.
There may also be pets as characters. A dog or a cat that is the child's loyal companion. For example, the dog might go on adventures with the child, or the cat might be a source of comfort when the child is sad. And sometimes there are bully characters too, who create conflict for the main child character in the story.