Resilio Sync Business - Resilio Sync Business is a solution to collaborate on shared assets.
Quip - Quip is the modern productivity suite that simplifies your life and helps your team get work done faster.
Just Social - JUST SOCIAL provides all the collaboration tools like enterprise social network, real-time document collaboration
Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
Slite - Your company knowledge
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.