How many different brands of golf balls is there?

well there are many different types of Golf balls some are expensive and some of them are dirt cheap. the different brands of golf balls is hard to know because some are being used which you havent heard of. i say though on the PGA tour around about 10-15 different brands of balls are used. Examples, Nike, Callaway, Bridgestone, Srixon, Titliest, Top Flite not (flight) and many other brands of golf balls are being used which i probably don't know about.