It is amazing how bad some things are documented and how many people are struggling to find the right information.
The next natural question would be: what other icon classes are available ? One sort of question where you start googling without ever finding a sophisticated answer to your question. You would expect to bump into some reference somewhere listing all those possible icon classes, but nada – nothing. Instead you find a lot of discussion threads where people discuss the very same issue, like for instance here and here. In the latter you read somewhere that all icons are available in /dojo-src/dijit/themes/tundra/images/editor.gif; this gets you part of the answer, at least you can see what icons are available, but you don’t get their class names.
After doing some more investigation I found all those class names actually listed in /dojo-src/dijit/themes/tundra/editor.css.