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.

RemoteTeam - Remoteteam.com helps remote teams become great places to work with the fully-integrated platform to automates payments and HR tasks.

Slack - A messaging app for teams who see through the Earth!

Swipes - Plan projects, take action and discuss.

GrowthList - A crowd-sourced list of growth hacks

ApproveIt for Slack - Get approvals in minutes, not days. Right from Slack!