The U-matic format, perhaps better known as 3/4 inch, was ubiquitous at TV stations in the 1970s and 80s as it was used for the original videotape “minicams” that replaced film cameras. Those used the big, bulky recorders that photogs carried as a large backpack or rolled around on a purpose-built cart. Combined with the camera and beltpack batteries plus other peripherals, it all was a lot to haul around. Although not specifically a videographer in those days, I still got to do that a number of times. Not fun, but it beat having to deal with film.Goodness knows some of these earlier videotape formats are not easy to find in the wild. I do, however, recall seeing a U-matic tape being among the various media sold at a local thrift store in Parma Heights that has since closed down.
U-matic was never considered a home format, but it did also show up in educational settings, libraries, churches, and other situations where video would be shown to a group of people. Probably plenty of those machines still floating around out there, though the mechanics had a tendency to wear out or become misaligned, thus eating tapes.
VX is an extremely rare format to find these days, even more so than V-Cord. I think it was only made by Quasar/Motorola, so there was no price competition. VHS had all sorts of companies selling the format, which kept its cost competitive.At the Internet radio station I volunteer at, one colleague of mine brought a Quasar VX VCR and a tape to the house where the station is located because the station owner repairs computers and other electronics by trade.
Akai VK might be even more rare than VX. The VK tapes can easily be mistaken for Betamax as the cassettes are very similar.