A new (and superb) Internet Archive blog post by Alexis Rossi includes direct links to some selected music, texts, films, and more published/released in 1923, now in the public domain, and available via from the IA.
But why are we focusing on 1923? Because for the first time in 20 years, new works are entering the public domain in the United States. And those works were all published in, you guessed it, 1923.
Along with the highlights the post also includes a link to 20,000 texts from 1923 available via The Internet Archive.
Direct to Complete Blog Post: A Public Peek into 1923
See Also: 1923 Publications (via HathiTrust)