I just ran across this very useful link for anyone who does arrangements or transcriptions:

“The Logos CopyLeft Pages” which has a handy list of composers who are (or are about to be in the public domain).

Thanks, CopyLeft!

Samples:Verdi, Franz Strauss, Dvorak, Albania, Joplin, Mahler, Saint-Saens, Sousa, Gershwin, De Falla, Webern, Elgar, Bartok, Revueltas, Ravel, Delius, Janacek, Puccini, Debussy, Grieg, Holst, Dukas, Glazunov, Respighi, Satie, Nielsen.

Works that will become public domain soon:

Richard Strauss (2019)

Kurt Weill (2020)

Arnold Schoenberg (2021)

Serge Prokofiev (2023)

Charles Ives (2024)

Reinhold Gliere (2026)

Jean Sibelius (2027)