A "predictable" picture book may sound ho-hum, but it is often just what the child, parent, reading specialist is looking for. Predictable texts are great fore shared reading. The child learns the pattern, repetition, rhythm or rhyme scheme and can "predict" what comes next. It also allows for pretend reading time, an early literacy skill, when the adult isn't helping and soon the child know the story. Think about children that want to hear the same story over and over again. It is becoming predictable. The child is learning.
Predictable books come in many forms and there are great resources for finding them. In my search to find some mentor texts for my picture book writing, I found these sites very helpful:
Monroe County Public Library Children's Booklists
University of Wisconsin- Polk Library