&what: Discover Unicode & HTML Character Entities : amp-what is a quick, interactive reference of 14,500 HTML character entities* and common Unicode characters, 8859-1 characters, quotation marks, punct...
AlsacréationS : Alsacréations est une communauté dédiée à l'apprentissage des standards web (W3C, HTML, XHTML, CSS) ainsi qu'à l'accessibilité numérique
Email Standards Project : The Email Standards Project is about working with email client developers and the design community to improve web standards support and accessibility ...
This site provides a collection of schemas that webmasters can use to markup HTML pages in ways recognized by major search providers, and that can also be used for structured data interoperability (e.g. in JSON).
Docusaurus : Easy to Maintain Open Source Documentation Websites
Zest Documentation Browser : Offline search tool for developers. Find what you need without the need for Internet access. Allows finding detailed information not available in docu...
CSSdoc : This is a draft to bring automatic documentation to CSS files, like its known for JavaScript and PHP files through JavaDoc/DocTags.
Strut : An HTML5 Presentation Editor. A GUI / Authoring Tool for ImpressJS and Bespoke.js
Source at https://github.com/tantaman/Strut