ASSONANCE: A close juxtaposition of similar vowel sounds; a repetition of vowel sounds without repetition of consonant sounds. Sometimes used as an alternative to rhyming in free verse.

Ape in a Cape: An Alphabet of Odd Animals by Fritz Eichenberg
The Recess Queen by Alexis O'Neill
Piggie Pie! by Margie Palatini
Piggies in the Pumpkin Patch by Mary Peterson
Cat in the Hat by Dr. Seuss
Green Eggs and Ham by Dr. Seuss
Sheep in a Ship by Nancy Shaw