Momixa - Pick two songs and get the perfect mix
Audio Hero - Over 250,000 royalty free music & sound effects for videos
Music Suggestions Ninja - Enter an artist's name & find similar, lesser known artists
TunePocket - Download 11,000+ royalty free music tracks and sound FX. Buy once, use forever. New music added daily. Save over 50% compared to most popular similar services. Incredible value!
Boil the Frog - Create a seamless playlist between any two artists
Free Music Archive - Interactive library of high-quality, legal audio downloads