Yamaha have only six fills, I believe. A full compliment is sixteen, including fill to self.

You see, the fill that goes from the busiest Var to the next less is different from the fill needed to go from the busiest to the simplest, And vice versa.

Some say this would complicate style production, but I disagree. At the moment, making a fill that does SEVERAL things well is harder than making several fills that only have to do ONE well, IMO.