I was searching for some comprehensive registry of FourCCs when I happened upon Sustainability of Digital Formats: Planning for Library of Congress Collections. They host an interesting, and recently updated, survey of all manner of multimedia formats including containers, video codecs, audio codecs, and text formats.

Also, I eventually found the Microsoft’s official list of registered AVI video FourCCs (and 16-bit audio codec identifiers): The IANA hosts it: http://www.iana.org/assignments/wave-avi-codec-registry. There is some very interesting stuff in there. Did you know that Dolby had an AC2 codec? And that their listed address is spelled incorrectly? (I know since their office is about 2 blocks away from where I work.)