Today we take mass production for granted. You go to a big-box store and buy a rope out of a bin. There are tens of thousands of identical ropes. Most fantasy settings are not set in an industrialize world. That means each rope was made by hand. In a world of handmade stuff it was common for a craftsman to sign their creation. For example, the rope maker could use a few specially colored threads in the weave that made all the ropes they made unique form all the other ropes. Samurai swords often have a signature on their tang identifying the maker.
A World Builder can use this to make each and every item in their world unique. A character goes to a merchant to buy a rope. The merchant says, “I have two ropes for sale. One from the famed rope maker Connehorn for 52 gold, or one from the lesser known Reanderei for 50 gold.” Five Guys Burgers and Fries uses this very idea in their stores when they write on the chalk board what farm grew the potatoes they used for their fries.
This opens up new adventures. The party tries to sell a sword they took off of some monster. The merchant says, “The famed smith Mance forged this sword four centuries ago, where did you get this?”