There are many folk song books with chords (and usually melodies, too) which are found in most municipal libraries. Some pertain to particular artists (e.g., Joan Baez , The Weavers, Theodore Bikel, Tom Paxton, Woody Guthrie) and others to eras or countries (e.g., Child Ballads or Songs Of The Old West). Use a topical search under "folk music" and you should find a lot of material. (If you don't have access to a fair-sized city library, the internet can give the same results, but I find it slower than the library if I just want to browse a wide selection of material.)

Genie