You can find them in children's storybooks. There are many classic collections that are full of such lovely stories. For example, the 'Fairy Tales for Bedtime' series often has really funny and heartwarming good night stories.
Another way is to ask your grandparents or parents. They usually know a lot of traditional funny good night stories that have been passed down through generations. They can tell you these stories in person, which makes the experience even more special.