In Six Revisions I’ve found two posts with links to 51 cheat sheets (AKA reference cards, reference sheets, etc.) related to web developing, including, for example colours (like this Web Safe Color Chart) tipographies, dimensions, (X)HTML tags, CSS properties, Keys for popular programs (like the Dreamweaver CS3 Quick Ref.) and many others. The posts are:
PS: another one recommended for web developers: Will the browser apply the rule(s)?