Did you know that Virgina Woolf wrote children's literature? James Baldwin, too (with illustrations by Don Freeman of Corduroy fame)? James Joyce? I didn't either, until I stumbled across this blog, "a compendium of children's books by twentieth-century "adult" authors currently out of print."
Here's a fun one for examples of amazing writing: Letters of Note, "correspondence deserving of a wider audience." If you ever teach Slaughterhouse Five, this letter from Kurt Vonnegut to his family when we was being held as a prisoner of war is worth sharing with students. This letter from Mark Twain calling a patent medicine salesman "an idiot of the 33rd degree" is both amusing and a tour de force of English syntax. You can spend hours browsing this site.