Wintersmith - Flexible, minimalistic, multi-platform static site generator built on top of node.js
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.
Nikola - Nikola is s static site generator tool written in Python.
Noizio - Feeling that the noise of the big city is too much for you to bear?
SleepJet - Plane ambient sounds to fall asleep ✈️
A Soft Murmur - Ambient sounds to wash away distraction.