1. Jamendo: This site offers a large collection of free music (including MP3s) under Creative Commons licenses.
2. SoundCloud: SoundCloud allows users to upload and share audio files, including MP3s, and many artists choose to make their music available for free download on the platform.
3. Musopen: Musopen focuses on classical music and provides free downloads of MP3s and other formats.
4. Free Music Archive: This site offers a diverse range of free MP3s, including music from various genres, time periods, and cultures.
5. Last.fm: Last.fm offers free MP3 downloads of selected tracks through its "Free Music" section.
6. Beatport: Beatport, known primarily as a platform for electronic music, offers a selection of free MP3 downloads from various artists and labels.
7. Amazon: Amazon offers a limited number of free MP3 downloads through its Amazon Music store.
8. Bandcamp: Bandcamp allows artists to set their own prices for their music, and many choose to offer MP3s as free downloads.
9. Audiomack: Audiomack is a streaming platform that also allows users to download MP3 files for free, mainly focusing on hip-hop, electronic, and alternative genres.
10. Noisetrade: Noisetrade offers free MP3 downloads in exchange for fans providing their email address or signing up for a mailing list.
Remember to check the licensing information for each track before downloading to ensure you have the right to use it for your intended purpose.