PiratePad VS ownCloud Documents

Firepad - Open source collaborative code and text editing that relies on Firebase for real-time data...

Etherpad - Etherpad is a highly customizable Open Source online editor providing collaborative editing in...

CryptPad - CryptPad is a collaborative office suite that is end-to-end encrypted and open-source.

eduPad - Real-time collaborative text-editor. No account required. Edits highlighted in authors color.

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.

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.