HelpCrunch Knowledge Base - Deliver instant answers to customers 24/7 with help articles
Quip - Quip is the modern productivity suite that simplifies your life and helps your team get work done faster.
Slab - Slab is a knowledge hub for the modern workplace. We help teams unlock their full potential through shared learning and documentation. Slab features a beautiful editor, blazing fast search, and dozens of integrations like Slack, GitHub, and G Suite.
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.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
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.