Interstate Batteries. They have all kinds of batteries. I had two obscure (to me, at least), very dead, button-type batteries in two different pedometers. I had no idea that the little button batteries were "watch batteries" in the trade. So I searched the number on the back of the first dead battery, and found the replacement. The service was prompt and the pedometers are firing.
CD RV Parts Center. We have been getting our camper ready for our first camping trip in literally years. In the interim, we bought a new car for towing and were having trouble with the "pigtail" that connects electrical system of the camper with that of the towing vehicle: it was too short. I thought, "I wonder if you can get an extension for those things?" I ran "RV equipment" on Google, and this was number one on the listing. Like the battery vendor, the key issue was whether I could find the item in the vendor's inventory. I didn't know that "pigtail" was a key word. But "extension" and "electrical" worked. I was a little concerned that the vendor was located in California, with me in Miami. But it was here in good order within a week with UPS ground. It was exactly what I needed.