freeplaymusic.com is a source I've used before, they've been around decades. bensound.com is one I found more recently and have used. Both are royalty free sources (for personal use). triplescoopmusic.com is a great source for commercial use as their prices are pretty reasonable to buy the rights to songs.
try this site Jamendo Music | Free music downloads the music don't have copyright and YouTube don't banned the videos or send messages about copyright violation