We play horse... just like in basketball.
I have a strike zone painted on the wall but you could use a pitchback. Set up a tee with a ball on it in front of the wall. Pitcher calls her shot (low & in etc... and adjust the tee accordingly) and if she hits the ball off the tee, the other pitchers have to match it... if they miss they get a letter. we will mix up it up each round with different pitches. Round one is a fb, round two is a cu, round three is a drop etc. And the winner gets to "start" the live bp at the end of practice.