The Sage islands are tolerated by the Capital Islands only because they do not see them as a legitimate threat. They are considered radical liberals but have an acceptable dislike of magic and no military to speak of.
There are a lot of old libraries and archives that likely contain things that survived the purging of magic. Some of the buildings in the larger cities are extremely old and contain basements, hidden rooms, and forgotten areas.
There is a city bellow the water off the south western coast that is known, but seldom interacted with.