I'm not aware of a list. Most of the settings you see in that file are set through QMC. That is the published/public interface for those settings. While there may be additional values available, I don't think R&D would publish a comprehensive list as the intent is to use the published interface (QMC) to make changes. The Help system in QMC is meant to provide the documentation for the available settings,
This is similar to QlikView Desktop settings where changes are made via the User Properties dialog.
Of course, there are exceptions when documentation, QT Support or village knowledge directs you to hand edit the settings.ini.