Quip - Quip is the modern productivity suite that simplifies your life and helps your team get work done faster.
Untools - Hand-picked tools for better thinking
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.
Mental Models - Thinking tools to help you navigate life better
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.
Notionery - Mental models made for Notion