In no particular order:

Where the Wild Things Are by Maurice Sendak
Green Eggs & Ham by Dr. Suess
Don't Let the Pigeon Drive the Bus by Mo Willems
The Grouchy Ladybug by Eric Carle
The Very Hungry Caterpillar by Eric Carle
Llama Llama Time to Share by Ann Dewdney
Harold and the Purple Crayon by Crockett Johnson
Chicka Chicka Boom Boom by Bill Martin Jr.
The Rainbow Fish by Marcus Pfister
The Monster at the End of This Book by Jon Stone
The Snowy Day by Ezra Jack Keats
If You Give a Mouse a Muffin by Laura Numeroff
How Do Dinosaurs Say Goodnight by Jane Yolen
Go Away Big Green Monster by Ed Emberly
Brown Bear Brown Bear What do You See by Bill Martin Jr.
Blueberries for Sal by Robert McCloskey
Bear Snores On by Karma Wilson
Corduroy by Don Freeman