https://web.law.duke.edu/cspd/publicdomainday/2020/ [duke.edu]
Here are some of the works that will be entering the public domain in 2020. (To find more material from 1924, you can visit the Catalogue of Copyright Entries.)
[...] Unfortunately, the fact that works from 1924 are legally available does not mean they are actually available. After 95 years, many of these works are already lost or literally disintegrating (as with old films5 and recordings), evidence of what long copyright terms do to the conservation of cultural artifacts. In fact, one of the items we feature below, Clark Gable's debut in White Man, apparently no longer exists. For the works that have survived, however, their long-awaited entry into the public domain is still something to celebrate. (Under the 56-year copyright term that existed until 1978, we would really have something to celebrate – works from 1963 would be entering the public domain in 2020!)