Some children's poetry classics include "Jabberwocky" by Lewis Carroll, "The Tyger" by William Blake and "Dirty Face" by Shel Silverstein. The former two were written in the 19th century, the latter in the 20th century.
"Jabberwocky" belongs to a tradition of nonsense poetry in which the rhythm and rhyme in the language of the poem are the main features. The meaning is partly inaccessible because many of the words are coinages whose meanings a person can only infer from the context or through in-depth etymological analysis. Such language is also known as jabber, speech that is mostly unintelligible.
"The Tyger" is a more directly understood poem in which the narrator ponders through a series of incantatory questions about who is responsible for creating such an awe-inspiring creature. The narrator seems confounded at times, a feeling intensified by the growing list of questions that lead to complex queries about the contradictory nature of the universe when the narrator asks the creature if whoever created the lamb also created the tiger.
"Dirty Face" is a more playful poem yet with thematic concerns that are just as serious. After an adult asks a child how the child's face got so dirty, the child produces a long list of actions that attest to adventurous spirit and powerful imagination of children, ending in a challenge to the adult to think of all the fun he is missing because he is no longer a child.