Apple iWork - iWork is an office suite by Apple.
CKEditor - Real-time collaborative future-ready rich text editor
OnlyOffice Docs - OnlyOffice Docs is an effective document creation and editing platform that provides you the options to create any kind of document with the collaboration of your team from any remote location.
Summernote - Summernote is a JavaScript library that helps users create WYSIWYG editors online.
Airborn - Create and edit documents online without sacrificing your privacy
Froala Editor - Froala Editor is a WYSIWYG HTML editor that enables rich text editing capabilities for the applications.