At the cave near the *spoiler* that has the rocks the NPC asks you to help dig through, the crate with the "pickaxes" is full of weapons that require the Martial Weapon proficiency. These are simple labor tools, I think it would be worthwhile to have some items in there that require the Simple Weapon proficiency as well, so people who can't use Martial Weapons can join in the dusty, back-breaking fun.