Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Noizio - Feeling that the noise of the big city is too much for you to bear?
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
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.
Slack - A messaging app for teams who see through the Earth!
zenmix.io - Ambient background sound generator