Here are two...
Law of Evil Items - it is against the law to sell items (weapons, rods, staffs, rings, amulets) that are known to be evil. Doing so will result in at least two years of hard labor and the confiscation of all properties.
Law of Fire - it is illegal to endanger public and private properties with magic or mundane means.
I also have some basic rules on life in areas and while not laws are lawful, some characters know these more than others (rogues urban, rangers rural, barbarians wilderness):
Urban: people are respectable to anothers home/property, you obey/know local laws.
Rural: You don't sleep in someones barn unless you ask, you don't kill farm animals, you share news of the road when asked, you help others on the roads.
Wilderness: You always annouce yourself when entering a camp, you do not leave a fire unattended, you don't ruin water, you don't take anothers mount (note: barbarians will raid others for horses as a right of passage but it is a raid on a herd not taking a mount).