I would like to point out that The Great Gatsby is PD in Europe or countries with life + 70, while it is not in the US. Therefore librivox won't do it, but you can

http://www.feedbooks.com/book/5543/the-great-gatsby

https://dimenovels.lib.niu.edu/
https://www.pulpmags.org/

These might be of interest

I have heard that Hitler's Mein Kampf is in the PD now. It would be interesting if anybody would find an English translation. (No, I am not a nazi. I run an non-profit educational blog called historyradio.org)