Effects

• BBC Sound Effects http://bbcsfx.acropolis.org.uk
• SOUNDMORPH https://www.soundmorph.com/sounds
• TRAILER MUSIC ACADEMY https://soundcloud.com/trailermusicacademy/sets/trailer-tools-vol-1-free

Music

• KB / Farbrausch (some songs under applicable copyright law) https://music.kebby.org

Images

• PIXABAY http://pixabay.com
• UNSPLASH http://unsplash.com

Films

• NATIONAL ARCHIVES CATALOG https://catalog.archives.gov/
• PIXABAY http://pixabay.com
• PUBLIC DOMAIN TORRENTS http://www.publicdomaintorrents.info/index.html
• ARCHIVE https://archive.org/details/feature_films
• PUBLIC DOMAIN MOVIES http://publicdomainmovies.net
• PUBLIC DOMAIN FLIX https://publicdomainflix.com

Visualizations

• NASA VISUALIZATION STUDIO https://svs.gsfc.nasa.gov