I loved No Such Things by Bill Peet as a kid and forgot about it completely for many years. I’d really love to find that old copy for my bookshelf now. (Bill Peet’s website is a 90s treasure.)
@john My favorite was Bill Peet's The Caboose Who Got Loose. I wish I had bought more of his books when my own kids were younger. It has been fun discovering his influence in old Disney films, like Dumbo.