I'm trying to get a list of valid Android permissions. I know the 'official' ones at http://developer.android.com/reference/android/Manifest.permission.html but it seems there are more out there.
There is no such thing as a comprehensive "list" for all permissions. New permissions can be defined by any application that wants to enforce its own: http://developer.android.com/intl/de/guide/topics/security/security.html#declaring.
Manifest.permission class lists the "system" permissions, and you're already aware of those. The other things you've listed aren't system permissions, but rather are specific to certain apps, and or are old names (ACCESS_LOCATION and ACCESS_GPS were pre 1.0 names, for example).
A grep for something like
<permission android:name= in the source would reveal all the included app permissions (for the open source apps), but in general you should stick to the documented permission names.