Newberry Library makes digital collection open access.

Including commercial use.

From the site: “The Newberry has announced a major revision to its policy regarding the re-use of collection images: images derived from collection items are now available to anyone for any lawful purpose, whether commercial or non-commercial, without licensing or permission fees to the library.”  Looks like Americana, mostly — so Western writers, take note.  There’s some stuff in there you might find of interest.