Classics:
* Alice from "Alice's Adventures in Wonderland" wears a white dress with a blue sash.
* The Little Mermaid (Ariel) in her human form wears a white dress with a blue bow.
* Snow White famously wears a beautiful white dress.
* Little Red Riding Hood (some versions) wears a white dress with a red cape.
Modern Characters:
* Eloise from the "Eloise" series often wears a white dress.
* Clementine from the "Clementine" series sometimes wears a white dress.
* Sophie from "Sophie's World" by Jostein Gaarder, though this is more of a young adult novel.
Other Examples:
* The Little White Dress by Debi Gliori is a book about a little white dress that goes on many adventures.
* Many fairy tale princesses wear white dresses.
This is just a small sample! Many children's book characters, especially female characters, wear white dresses.
To find specific examples, you can search online databases like WorldCat or Goodreads.