Sononym - Finally, a sample browser that understands audio
Noisli - Noisli is a fantastic background noise and color generator for working and relaxing. Online soothing ambient sounds like White noise, Rain and Coffee Shop.
Soundly - Functional music for better sleep, focus and relaxation
Noizio - Feeling that the noise of the big city is too much for you to bear?
Samplism - Feature-packed, audio asset manager for Mac.
zenmix.io - Ambient background sound generator