That list doesn't even include the very first card grading service, Certified Baseball Card Service (CBCS), which was started by John Bottorff in late 1987. The April 7, 1989 Sports Collectors Digest had a long article that included an interview with Bottorff. I posted that article here, though the photo quality is pretty poor (sorry -- I'll have to post better pictures sometime).
http://net54baseball.com/showthread.php?t=223192
At the time, CBCS was still the only card grading service, but later in 1989 Alan Hager founded the second one, Accugrade Sportscard Authentication (ASA). Hager came up with the 1-10 grading scale that's familiar today, and I believe he patented it or something, so that when David Hall started PSA in 1991, he had to pay a licensing fee to Hager. By the mid-90s, PSA and ASA were the two biggest card grading services, with many other small ones trying and failing to gain a foothold. But Hager was kind of a skeevy character; I don't remember all the details, but ASA eventually crashed and burned, leaving an opening for SGC to come on the scene in the late 90s.
The early history of card grading companies is another area of hobby history that I'd love to write up if/when I ever have the time.