Clean and humorous titles by renowned comedy writers, such as Theodor Seuss Geisel or P.G. Wodehouse, are available in many public libraries. Classic short stories, such as "The Cat in the Hat" by Dr. Seuss or "The Model Millionaire" by Oscar Wilde, are common.
The availability of particular books differs between libraries, and smaller local libraries sometimes lack variety. When a book is unavailable, library staff often can help, perhaps by ordering a book, though policies may vary.
Public domain comedy classics can be accessed online through archival websites, including Project Gutenberg, that have categories dedicated to humorous works. Archive.org hosts the American Libraries collection, which contains much material contributed by small libraries, including many clean and humorous stories.