&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...
schema.org : 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 als...
Collection of thinking tools and frameworks to help you solve problems, make decisions and understand systems.