I'm a longtime fan of Dan Goodsell's, and you will be too if you take a look at his blog and the adjacent pages he's done, using the huge amount of keen things from his collection. Here's a small taste from his blog, "A Sampler of Things":
Neat, eh? He posits that the great illustrator Richard Scarry might have done these cereal boxes--there's more boxes shown on his latest post. Go there now!