Here are a some picture book ideas:
Just a Dream
by Chris Van Allsburg
The Wump World
by Bill Peet
by Dr. Seuss
Many nonfiction books and articles (something from Time For Kids
for example) are written to persuade the reader to: conserve energy, get involved in saving endangered species, to exercise and make healthy food choices, etc.
I've used the books the pp mentioned
I Wanna an Iguana
by Karen Kaufman
Dear Mrs. LaRue: Letters from Obedience School
by Mark Teague
to teach persuasive writing which . . . would of course tie into teaching author's purpose in reading.