I would like to see a sand pit. Sand could be used in construction and also for another new workplace: glass maker. Glass maker could make sand, water, and charcoal + iron or steel tools into glass beads or glass bottles, perhaps even for windows in even larger and fancier stone houses as a required construction material.
Bottles could be used to store alcohol, which would be a way to allow for the Inn to produce a surplus of alcohol, store it in bottles, and then store the bottles in a barn. Alcohol could thus be a valuable commodity for stockpiling and trading.
Secondly, I would like to see a building for construction on water's edge called a "shore shack" or "clam digger" or something. Resources produced would be shellfish as food (slightly less kcal than fish, same health benefit) and shells, which could lead to a new workplace: jeweler, which could create jewelry from shells and other resources - such as flax, glass beads, etc. Jewelry would give a happiness bonus and would also be a valuable commodity to trade.
Third, I would like to see a two new workplaces for the production of paper. First, a new workplace called a pulp mill that takes logs and charcoal and creates wood pulp, and then a new workplace called a Papermaker could create paper, which would either be required for education or research (at the keep) or would speed up/enhance those processes.