It's almost 2019, which will bring the first new batch of US public domain works in over 20 years:
https://law.duke.edu/cspd/publicdomainday/2019/
This "public domain day" used to happen every year until 1998, when 20 years was added to copyright terms for no real reason other than that large companies like Disney wanted it.
Copyright currently lasts 95 years in most countries, but until the late 1970s it was 56 years, or even shorter if copyright wasn't actively renewed.