iSpring Suite - A comprehensive yet easy-to-use authoring tool for creating professional online courses like a pro – even if you’re a complete beginner.
CKEditor - Real-time collaborative future-ready rich text editor
Articulate Storyline - Articulate Storyline is a program that allows you to create interactive courses of any kind with templates and a simple system. There is a free trial offered so that you can determine whether you want to use the program further or not.
Summernote - Summernote is a JavaScript library that helps users create WYSIWYG editors online.
Brainshark - Brainshark sales enablement solutions help deliver the content you need to sell, market, educate and inform with maximum impact – all within Salesforce.com.
Froala Editor - Froala Editor is a WYSIWYG HTML editor that enables rich text editing capabilities for the applications.