Knotable VS Indigrid

Scrapbox - A new style of note-taking that lets you create, discuss, and learn together in one self-organizing space.

Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.

Additor beta - Pocket and Evernote got a minimal and collaborative baby

Nuclino - Nuclino works like a collective brain, helping teams bring all their knowledge, docs, and projects together in one place. It's a modern, simple, and blazingly fast way to collaborate.

Unit Notes for iOS - A simple and powerful note-taking app.

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.