Website Builder
Free · Open
A cross-platform WYSIWYG web and EPUB editor based on the Firefox rendering engine, supporting HTML5, CSS3, and SVG editing
AlertCaution is advised.

Free · Open
Quickly generates static websites from content written in Markdown or other formats by passing the content through user-defined templates
AlertCaution is advised.
Paid
Visual web editor for professionals, integrates with HTML, CSS, Bootstrap, WordPress, and more
AlertCaution is advised.