The Bare Bones Guide to HTML lists every official HTML tag in common usage, plus Netscape and Microsoft extensions.
Version 4.0 of the Guide is designed to conform to the HTML 4.0 specification. For official information on the development of HTML, see the World Wide Web Consortium's HTML activity statement.
I regret that, due to time constraints, I'm no longer able to answer individual questions about HTML or Web design. The resources listed in the left-hand column should address the most common questions.