What Could Have Entered the Public Domain on January 1, 2018?

"Current US law extends copyright for 70 years after the date of the author's death, and corporate “works-for-hire” are copyrighted for 95 years after publication. But prior to the 1976 Copyright Act (which became effective in 1978), the maximum copyright term was 56 years—an initial term of 28 years, renewable for another 28 years. Under those laws, works published in 1961 would enter the public domain on January 1, 2018, where they would be “free as the air to common use.” Under current copyright law, we’ll have to wait until 2057."