Here are things I and my co-DM have developed for Bugbears for Breakfast and done some detail work on. More will follow.
Chartered Adventuring Companies
To speed up the exploration of the Found World and reduce the cost of doing so, most governments in the Old World now issue Adventuring Charters. The cost up front is negligible and mostly involves establishing that the members of the charter company have the financial means to purchase transportation through a Moon Gate. The charters allow adventurers to explore the Found World, gather up what riches they can, and then pay a Charter Fee to return to the Old World with their wealth. The Charter Fee is very steep and is one of the revenue generators for the issuing governments. Some governments allow chartered companies to make incremental payments until the entire amount is paid, but increase the total fee by 20 to 50% if this option is taken.
The advantage of issuing Adventuring Charters is manyfold: adventurers explore the territory being colonized, adventurers clear out dangerous monsters, adventurers provide income (in the form of the Charter Fees), adventurers return as wealthy (and taxable) citizens, and adventurers are not hanging around the Old World looking for trouble.
Goldland Crossing is built in the ruins of a walled city on the coast of the Southern Sea. It surrounds one of the better known Moon Gates. The ruins could once have sheltered thirty to forty thousand people, but is now home to approximately 5000 people. The two inner districts (the Gate District and the Market District) are mostly rebuilt and well patrolled by the city guard. The Lower Docks have been isolated from the rest of the city by the New Wall and are also heavily patrolled. The upper Docks and the three outer districts have only received spotty attention and only the routes from the main gates to the inner districts are patrolled with any regularity.
Everyone living in the city is required to spend one day in ten serving in the city guard, providing a pool of nearly 400 guardsmen on any particular day. Most citizens see this as a necessity for keeping the city safe and willingly spend the time. Anyone missing an assigned day is rescheduled and assigned a penalty day, which must also be served. A side effect of this is a willingness of the citizenry to assist guardsmen who call for assistance (as next time it could be them needing the help). In addition to patrolling the city, guardsmen also are assigned to work details, which is how the New Wall was constructed.
With a high number of chartered adventuring companies based in the city but usually out in the wilderlands, theft of property from homes is dealt with harshly in the city. Those caught and convicted are publicly executed (and remember, the use of magic to prove guilt is regularly used).
Adjacent to Goldland Crossing is Otter's Bay, a bay that is unique in several ways: the bay is uniformly 30 ft deep, there is a conspicuously vertical cliff surrounding three-quarters of it, and the ruins of an ancient city sits at the bottom of the bay, with taller buildings poking up above the waters. It is clear to most that once the city was above the waterline and was sunk by supernatural means. Evidence of this is easy to find – there are the remains of roadways that lead to the edge of the cliffs and stop, only to resume at the base of the cliff, 30 ft under water, continuing into the sunken ruins.
The bay comprises Otter's Barony, a fief granted to a human named Otter. Otter was once an apprentice shipwright and built the first ship able to sail back to the Old World, bringing the riches of the Found World to the Old World's attention. In return for this service, Otter was granted the bay as a hereditary fiefdom and the right to collect docking fees in the bay named in his honor. The current baron, Otter III, maintains these rights, plus runs a business harvesting oysters and owns several fishing vessels that work the Southern Sea, providing fish for Goldland Crossing.
The population of Otter's Barony lives in the portions of the sunken city that are still above the water's surface. The walls are made of stone and those buildings still standing are very sturdy. If the building had stone floors, they are still in use, but many buildings have had internal structures of wood added. Most buildings have at least limited oyster and clam beds in their lower structures, which provide food and a limited crop the tenants can sell in Goldland Crossing on market days.
Occasionally an aquatic monster will find its way into the bay and endanger the oyster divers and other residents. The baron will place a poster in the Goldland Crossing market and hire adventurers to deal with the monster for either a fee or the right to set up in one of the unused towers in the bay.