A fairly comprehensive list is available at the link below.
Some sites that offer public domain comic books include Digital Comic Museum, Comic Book Plus, and Project Gutenberg. These sites provide a variety of comic books from different eras and genres that are available for free and legal download.
Yes but with qualifications. It appears that the original copyright on the Fiction House artwork & stories was never renewed and has lapsed into the public domain. However many of the various characters are still protected by trademark (Sheena Queen of the Jungle, the Spirit, etc) and cannot be used without the proper permissions.
Some popular websites where you can find public domain MIDI files include FreeMidi.org, PublicDomain4U.com, and Musopen.org.
Wolverine is a fictional character that belongs to the domain of comic books and superheroes. Specifically, he is a popular character in Marvel Comics and has been featured in numerous comic book series, movies, and TV shows.
Data not in the public domain
Some popular public domain board games that can be enjoyed by people of all ages include Chess, Checkers, Backgammon, and Go.
With the exception of Plastic Man, Blackhawks, and the Spirit, all Quality Comics characters, as originally depicted, have fallen into the public domain. The new versions of those characters ("retcons") are property of their respective companies.
The most popular example of software in the public domain is SQLite. There isn't too much software in the public domain, as most of it is licensed under a very permissive free software license, like the BSD license.
"Heart and Soul" was composed by Hoagy Carmichael and is still under copyright protection. The song was published in 1938, so it will enter the public domain in the United States in 2034.
One can find pictures of puppies that are considered to be in the public domain on public domain picture collection websites. These are a few of those: Wikimedia, PublicPhoto, Pixabay, PD photo, Photos Public Domain, Picdrome, Alegri Photos, Free Photo Gallery, Public-Domain-Photos, 4Free Photos, Free Stock Image Site, Public Domain Files,Public Domain Depot, Open Galleries, Free Images Collection, Free Digital Photos, Public Domain Photo, Project Public Domain Pictures.
Center for the Public Domain was created in 1999.
Union for the Public Domain was created in 1996.