W3Schools is a web developers site, with tutorials and references on web development languages such as HTML, CSS, JavaScript, PHP, SQL, and JQuery, covering most aspects of web programming.
CSS-Tricks is a helpful website about all things entail web design and web development.
Advanced Eyedropper, ColorPicker, Color Analyzer and other colorful goodies, for Chrome and Firefox.
DeviantArt is the largest online social network for artists and art enthusiasts, and a platform for emerging and established artists to exhibit, promote, and share their works with an enthusiastic, art-centric community.
Siteliner is a free service that lets you explore your website, revealing key issues that affect your site's quality and search engine rankings: Duplicate Content, Broken Links, Page Power and Reports.
"Can I use" provides up-to-date browser support tables for support of front-end web technologies on desktop and mobile web browsers.
Font Squirrel is a collection of free fonts for commercial use. We scour the internet for truly free, AND, high quality fonts. We also have the world's greatest, and only of it's kind, @font-face font generator. If you own a @font-face license for your fonts, you can use the generator to create web-kits, or to tweak you existing kits to improve rendering and file sizes.
MyFonts is a digital fonts distributor, selling fonts through the www.myfonts.com web site.