Sites that offer music and sound published under Creative Commons:
YouTube Audio Library - "Browse and download free music for your project." Includes sound effects and genres. https://www.youtube.com/c/audiolibrary-channel/featured
ccMixter - Music on this site is licensed under a Creative Commons license. You are free to download and sample from music on this site and share the results with anyone, anywhere, anytime. http://ccmixter.org/
Archive.org - "All music in this collection is from trade-friendly artists who have opted in and is strictly non-commercial, both for access here and for any further distribution." https://archive.org/details/etree
Jamendo - "Free music downloads and streaming. Discover and explore 600000+ free songs from 40000+ independent artists from all around the world." https://www.jamendo.com/?language=en