CKEditor - Real-time collaborative future-ready rich text editor
Redactor Text Editor - WYSIWYG html editor.
Summernote - Summernote is a JavaScript library that helps users create WYSIWYG editors online.
PHP Markdown - PHP port of the Markdown text-to-HTML conversion tool for web writers.
Froala Editor - Froala Editor is a WYSIWYG HTML editor that enables rich text editing capabilities for the applications.
TinyMCE - TinyMCE is a content editor that functions as a plug-in for Wordpress websites.