Ever wonder what colors to use with an image? Upload your image to Pictaculous and get a custom colour palette.
The Colour Contrast Check Tool allows the user to specify a foreground and a background colour and determine if they provide enough of a contrast "when viewed by someone having color deficits or when viewed on a black and white screen.
The cssTypeSet service allows you to quickly and easily develop CSS styles for your web site text.
The W3C Validation Service validates multiple versions of XHTML and HTML, outputting many useful errors and warnings.