There is also the investigation of sealed historic ruins, huh?”
As the sole exception, I guess there is the exploration of dungeons and structures created by the ancient magic civilization.
For some reason, the majority of them are infested with domains where monsters dwell. Because there are troublesome traps and powerful monsters roaming among those, they usually are prohibited to be trespassed due to the kingdom’s decision.
Although a new one occasionally gets discovered as well, it seems there are many cases of those who raided it without having prepared properly never to return again.