Bob, I think you are confusing two things, thus arriving at the wrong conclusion. I'll highlight the problem area as I see it.
You see, if you
ask for types of hair, you should accept an answer to that question. Instead, you mix up hair "grades" (to use the marketing slang word) with types of knots made with said hairs.
Besides which, I don't think anyone will say that all silvertips are created equal. The hairs can be grey(ish) badger bleached to resemble silvertip, or they can be cut into funny shapes, thus altering their backbone. But again, this has nothing to do with the hairs themselves.
So: There are three types of badger hair, black, grey, silver. Then there are two types of knots, three band and two band. The rest is marketing smoke and mirrors used by brush vendors to advertise their products as being somehow special.