If you can find some info or are familiar with the Bigger, Faster, Stronger dot drill it is great for foot quickness as is the jump rope.
We also have a "footwork grid" painted on the floor of our indoor facility.
On the floor we paint four sets of footprints; the first set (of two painted feet) are the catcher's recieving position, the second set are at the landing position for a jump-pivot pick-off to 1st, the third set is for a jump-pivot throw to 2nd, the last set is for a step behind throw to third. Inside the painted foot print (which could just as easily be a simple dot) we write, with a permanent marker, the appropriate number (R,1,2,or 3) to help identify them further.
We do, in rapid succession, each set three times, jumping back down to the receiving position after each move and we time the total set and keep records. Our catcher's love it.
So (in case this hasn't been explained clearly), you start in your receiving position, on the "go", the watch starts and the catcher executes the 1B footwork then back down into the rec. pos. and repeats this two more times. He continues to do three reps thru the footwork to 2nd, then 3rd. When his feet return to the rec. pos. the last time the watch stops.