The easiest way to search for the appropriate industries is doing an internet search.
I settled on three major companies for my switching layout.
1. Georgia-Pacific, well-known for its paper and tissue products
I assembled the backdrop structure on the left side from DPM wall sections and for the right brick wall I used plain styrene and laminated the brick sheets to it. The walls are all attached to the backdrop with double sided tape.
2. Acme Packing Company, formerly known as Indian Packing Company that was involved in the canned meat industry. Today the company is remembered as the namesake of the Green Bay Packers. The football team took its name after Curly Lambeau, a shipping clerk for the company, successfully asked the company's owner for money for jerseys and use of the company's athletic field in 1919 (the stadium of the Green Bay Packers is named Lambeau Field)
The Acme Meat Packing Company cloese in June 1943 because of supply shortages related to WWII and never reopened after the war.
I absolutely wanted a reference to the famous football team on my layout, so although the company doesn't exist any more, I still have a warehouse with a faded sign, remebering it.
This structure is completely scratchbuilt by laminating brick sheets to a plain styrene sub-base. The windows and loading doors came from my scrap box. The canopies above the loading doors are from Auhagen.
I added blowers and air vents from Rix, Kibri and Auhagen
3. Procter & Gamble is manufacturing paper products in Green Bay, but as I already have GP as a paper industry I use the P&G structure as a distribution center for the other brands they sell.