Music For Makers - Licensing good music has never been this easy.
Freesound - The Freesound Project is a collaborative database of Creative Commons licensed sounds.
Fugue - Free and premium stock music for your videos, games, and UI
Sample Focus - The easiest way to find the perfect audio sample
Thematic - Free Music for YouTube Videos & Creators • No Copyright
Moody sampler - A cloud connected audio sampler, including 1000+ instruments