This post is primarily for willshetterly & coffeeem, since we were just talking about a couple of my favorite books and I wanted to share some detailed information, but the rest of you are welcome to read it as well.

A book that is wonderful and whimsical and heartwarming and beautifully illustrated is Michael Bedard's Sitting Ducks.

The other book I mentioned is not only all of the above, it warms my little anti-establishment heart as well: Berkeley Breathed's Goodnight Opus. A tip: if you can find a used hardbound copy of Goodnight Opus in good condition, you'll want to get it instead of the paperback edition—the printing of the paperback is shockingly poorer (although still acceptable).
Finally, I hadn't mentioned it, but while I'm thinking along these lines, I should mention the wonderful book Gordon Garb (bless his black little heart) gifted Gavi with back when she was too young to read (although I imagine y'all already know of it): Daniel Pinkwater's The Big Orange Splot.