Doc’s first appearance was in 1933, so you have three years to wait.
Weird Tales started in 1923, so its first eight years are now in the public domain. Lovecraft started publishing there also in 1923, so much of the Cthulhu mythos is already p.d. if that’s who you’re looking for.
Earlier this year I bought an anthology on Kindle that republished the first eight Hardy Boys books. The original texts from the 20s, not the rewritten versions that came out in the 1950s and are still available today. Probably a Nancy Drew version will follow.
I did notice that the anthology I bought was called “The Original Adventures of Frank & Joe Hardy.” They seem to be very careful not to use the phrase “The Hardy Boys,” which is probably still an active trademark.
I was under the impression that H. P. Lovecraft’s original copyright was never renewed meaning people could have been writing Mythos stories as early as 1940. I think it’s kind of a niche genre that doesn’t really scream money
Many magazines in those days did not register their copyright, or if they did failed to renew the copyright after 28 years as was the law before 1976. Problematically, it’s a royal pain to track down either registrations or reregistrations, because the Library of Congress records are incomplete and almost impossible to search. When I edited an anthology I paid their research staff to do a search of some titles for me. Each cost $40 or $50 three decades ago. (One painful reason why my entire advance was gone before the book was published.) I don’t know if they still even do these searches.
The point of the 95-year limit on copyright is to provide a legally airtight case for reuse no matter what happened in the interim. Well, as long as you avoid the loopholes, like copyright protection on a continuing character’s traits from within the 95 years, or trademarks on the character, or whether they are objects with longer protections, like sound recordings, or other arcane stuff. Mostly, though, materials in the public domain can be reprinted in any form, and reused or repurposed in whole or in part. Google Books can now release the full scanned versions of items from 1930 they previously had to hide, for one good thing. Nevertheless, 99.99% of stuff public as of today is of no interest except to specialists, historians, or voyeurs, which is why the new year isn’t much of a big deal except to people like me. Historians, I hastily add; not voyeurs.