Chinese reading materials for Middle schoolers who had gone to Chinese immersion elementary school

A friend's kid went to Chinese immersion school for their elementary school. They have decided to move on to regular school. However, they would like to keep having some exposure in Chinese. One parent of the child is a native speaker. I'm posting here to see anyone knows a list of classics that Chinese kids would read? They are looking for sources to get Chinese reading materials too! Thanks in advance!