Another thing. A few weeks ago I linked to an IMDB page showing what movies were released in 1930 (and would have gone into the public domain). Often it is very difficult to search for pre-1923 authors, but this site helps somewhat. This page lists all the authors born in a particular year, and you can troll through 1850-1900 to find some pretty good finds before 1922.
Some examples: Robert Barr,Mary Wilkins Freeman, Rosa Campbell Praed , Howard Pyle , Robert Cromie, F. Anstey, Vernon Lee, Edwin Lester Arnold, Gertrude Atherton, George Griffith, Edith Nesbit, John Meade Faulkner, Richard Marsh, Count Eric Steinbock, Jerome Jerome, Fergus Hume, Kenneth Grahame, J.M. Barie, W.J. Wintle, Morgan Robertson, Clemence Housman, Christopher Blayre, Eden Phillpots, M.R. James, Wirt Gerarre, A.C. Benson, W.W. Jacobs , J.S. Fletcher, Robert Barr, Arthur Machen,
Sir Arthur Quiller-Couch, May Sinclair, Feodor Sologub, Allen Upward, Marie Corelli, H.B. Marriott-Watson, John Jacob Astor, Robert S. Hitchens
, Maurice LeBlanc, Barry Pain, F. Marion Crawford , M.P. Shiel, Baroness Orczy
, AEW Mason, Laurence Housman, Grace Livingston Hill , Robert W. Chambers, Violet Hunt (none of her works are scanned, although many are in the public domain!), C.J. Cutcliffe Hyne
, E.W. Hornung, E Douglas Fawcett, E Phillips Oppenheim, Edward Lucas White (stopping at 1866 birthdate).
(I’ll continue this list when I have time).
Also, I’ve been using Martin Seymour-Smith’s reference guide, New Guide to Modern World Literature to look up copyright information.