It’s time to start designing from the ground up. For a fashion designer that means finding vendors who will supply the zippers, snaps, rivets, toggles, buttons, etc.. Designers usually deal directly with the manufacturer or with an agent who represents different factories. Today there are very few American based vendors, most are overseas (wish I learned Chinese when I was little).
Vendors provide sample cards, books, or catalogs of their components for designers to keep in a library. As a collection is designed, designers refer back to this library. Vendors may add new components each season that reflect trends. Once a library is built, it is constantly updated.