Parker was one of the best arms for a long time, and one of the best in baseball, period.
Another great arm, for a much shorter time, was Glenn Wilson. Could not run him at all. And if you were slow and hit a single to right, you better be on your horse out of the gate or he would throw you out at first.
But the best throw I have ever seen was Bo Jackson throwing out Harold Reynolds at home. Reynolds was one of the faster guys in the game at the time too.