So many amazing illustrators to choose from as favorites. My tops are
Howard Pyle ...the master illustrator.
Bernie Fuchs...an amazing illustrator. There aren't many good samples of his children's illustrations online, but I have nearly every children's book with them in it.
Helen Ward is another genius at illustrating. My favorite book of hers isn't listed here. It's a Christmas story with all of the animals in the stable.
Leo and Dianne Dillon...an incredibly gifted and versatile team (once again, not much of their gorgeous work shows up online. It seems that all of my favorites shy away from being shown online. I guess they don't need to advertize their work)
Kinuko Craft rich, luminious gorgeous paintings...incredibly detailed with such a sense of atmosphere.
Gennady Spirin..absolutely amazing work.
More include Jerry Pinkney and David Diaz