Was looking for a list of this on the net but I couldn't find anything, so I found it in the source code. :P (This is current as of 4.0.206.0)

url_constants.cc and browser_about_handler.cc

This isn't very descriptive to non-techies but I just wanted to post the reference.
This doesn't list everything I don't think, at least, it's missing about:version.
The first section of definitions (kAboutScheme through kViewSourceScheme) are what go before the : in the URI.
We should all know what ftp, http, https, javascript, view-source, and mailto do (and probably file). But just for reference:
file:///Drive:/path/to/file.ext Example: file:///C:/myfile.txt
javascript:js code Example: javascript:alert("Hi");
mailto:email@domain.tld Example: mailto:myfirend@gmail.com
For information on the data URI scheme see here.
For information on the feed URI scheme see here.
I'm not sure how to use the gears URI scheme, it won't let me enter such a URL.
print:webpageurl I assume, but I don't have a printer to try it with.

As for the rest of them, I can't be too sure what they all do, but I'll tell you what I've figured out.
chrome-internal: These URLs cannot be entered into the omnibox.
view-cache: shows you all the files in your cache with links to view the HTTP headers received when you got the file, as well as a hex/ASCII view of the data.
chrome-user-script:*.user.js where *.user.js is the filename of the installed User Script. Shows you the source of that User Script.
about: Shows you your version information of Chrome and WebKit and stuff.
about:version Same as above.
about:blank Blank page.
about:cache Same as view-cache:
about:memory "Stats for nerds" as linked to by the Task Manager
about:memory-redirect Redirects to "about:memory"
about:terms Google Chrome Terms of Service.
about:dns View DNS request history.
about:histograms "Histograms"..not sure what that means :P looks like benchmarks to me.
about:objects Listed, but it doesn't seem to display anything..
about:stats Displays stats about V8 and stuff. Only able to render if you use the command line switch --enable-stats-table
about:plugins Shows all your plugins, if they're enabled, etc etc.
about:credits Shows all third-party libraries used in Chrome's creation with links to their homepages and licenses.
about:linux-splash Listed, but it doesn't seem to display anything.. Might be linux only.
chrome://about/* Where * is what normally goes to the right of a colon in and "about:" URI. It's the same thing as about:*, just more typing. lol This is what all "about:*" urls are routed to.
chrome://theme/* Where * is the name of the piece of the current theme. For example: theme_frame, theme_frame_incognito, theme_toolbar, css/newtab.css At least that's all I can find in the source that work.
chrome://thumb/URL Where URL is a URL you've visited, such as http://www.google.com
chrome://favicon/URL See above.
view-net-internal:* View network internals, currently only your proxy configuration. You can also use any of the URL listed on that page to view only a specific one. * can be one of the strings listed after the slash in the URLs listed on that page, for example: proxyservice
about:net-internal/* Mapped to ]view-net-internal:*
about:crash Show the crash page.
about:hang Constantly loading.. ie. hangs the page.
about:shorthang Constantly loading.. ie. hangs the page.
about:inducebrowsercrashforrealz Crashes the browser. lol Seems to only be here temporarily.

Self-explanatory/already known:
chrome://extensions/
chrome://history/
chrome://downloads/
chrome://newtab/

So yeah just basically hunting through the source and stuff for technical information cause the wiki sucks so hard. :S Figured I'd post these results. I'll edit as I find more info.

Thanks Waha, url_constants.cc is the one to bookmark...

Originally Posted by Luc VN

Thanks Waha, url_constants.cc is the one to bookmark...

Those links are from the 3.0.189.0 source code back-up, if you want to stay up to date come a new version, bookmark the ones in the trunk. ie. url_constants.cc and browser_about_handler.cc
:]

Also,

chrome://thumb/URL
chrome://favicon/URL

@Kyrax I fail to make this work?
A bit more info about the exact format?
Or even better a sample?

chrome://thumb/http://www.google.com
chrome://favicon/http://www.google.com

http://en.wikipedia.org/wiki/URL
URL includes the protocol used. Don't forget 'http://'

Also, this only works for websites that you have visited. There is talk on Chromium to change this and enable calls to it from the Chrome API.

Aha, I was trying this on not visited sites... Thanks.

Originally Posted by Kyrax

Also,

chrome://thumb/URL
chrome://favicon/URL

Added them to the post, thanks. :]

Updated for the latest version.

im trying to use the chrome://thumb in my extension but it gives an error saying that it is trying to use an local url. can anyone say what is the problem