Firepad - Open source collaborative code and text editing that relies on Firebase for real-time data...
Adobe Acrobat DC - Make your job easier with Adobe Acrobat DC, the trusted PDF creator. Use Acrobat to convert, edit and sign PDF files at your desk or on the go.
CryptPad - CryptPad is a collaborative office suite that is end-to-end encrypted and open-source.
Wondershare PDFelement - All-in-one PDF editor
eduPad - Real-time collaborative text-editor. No account required. Edits highlighted in authors color.
Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.