Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
CKEditor - Real-time collaborative future-ready rich text editor
Invision - Prototyping and collaboration for design teams
Summernote - Summernote is a JavaScript library that helps users create WYSIWYG editors online.
Sketch - Professional digital design for Mac.
Froala Editor - Froala Editor is a WYSIWYG HTML editor that enables rich text editing capabilities for the applications.