Youtube offers copyright free music here:
https://www.youtube.com/audiolibrary
Free Music Archive offers a wide selection of music:
https://freemusicarchive.org/
Mixter features a wide range of music here: http://ccmixter.org/
MusOpen offers a wide selection of music genres here: https://musopen.org/music
New York Public Library features a wide selection of public domain material here:
https://digitalcollections.nypl.org/
You can search YouTube for copyright free and creative commons licensed videos by applying the appropriate filters in the search function.
The US National Archive features a wide catalog of searchable moving images here:
https://catalog.archives.gov/ and here https://www.youtube.com/user/usnationalarchives
The National Library of Congress in the US features a wide collection of public domain material here: https://www.loc.gov/collections/national-screening-room/
NASA offers all of their images copyright free here:
https://images.nasa.gov/
Archive.org features a wide selection of public domain sound and images here:
https://archive.org/
Vimeo content creators make their material available under the creative commons license here: https://vimeo.com/creativecommons
US National Parks have a small selection of pubilc domain videos here:
https://www.nps.gov/grca/learn/photosmultimedia/b-roll_hd_index.htm
Unroyalty on YouTube is a channel that offers a wide range of sounds, music and videos here: https://www.youtube.com/@UnRoyaltycom/featured
Mazwai offers a wide selection of common creative video stock footage here: https://mazwai.com/stock-video-footage