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.
Quip - Quip is the modern productivity suite that simplifies your life and helps your team get work done faster.
Toby for Teams - Better bookmarks, now with collaboration baked in 🔖
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.
Planyway - Visual project management for Jira and Trello: manage resources, build project roadmaps, use time tracking.
Wiplo - The easiest way to organize and run your business workflows.