These are some great drills from former NFL QB Todd Kreuger to help quarterbacks improve mobility, ball security, and their response to various situations that come up in the course of a game.
Globetrotter
This is an excellent drill for ball security. Quarterbacks work the football in a circular motion around their head, under their arms, around their waist, around their knees, around each knee, weaving through their legs and finally "playing catch" between their legs.
Coaches shout commands of which body part the ball revolves around--usually starting with the head and working downwards. Coaches also shout the command "reverse" which changes the direction the ball is rotating. This should be done numerous times.
The drill concludes with five 'drops'--the quarterback dropping the ball and then grabbing it. This is done with five drops with the power hand and five drops with the off- hand.
Toss sweep and option drill
Set up a line of quarterbacks holding footballs with the coach in the "Running/Pitch Back" position. The coach should be in a position behind and off to the side of the quarterback--where a running back would be receiving a toss sweep or an option pitch.
The quarterback faces away from the coach/running back, in a position where he would be taking a snap from center. Quarterback reverses out and executes a toss sweep to the coach. (This simulates either a toss sweep or a quick pitch play.)
The quarterback then moves to the other side until all quarterbacks have executed the pitch. Then the beginning quarterback again executes the pitch to the coach and all other quarterbacks follow till all the quarterbacks have executed a pitch both to the right and to the left.
Now the quarterback executes an option pitch in the same manner. If the type of option your team runs has an inside or outside veer dive fake then this can be simulated in the drill by the quarterback. In the option phase of the drill the coach yells "pitch" and the quarterback breaks down and executes a pitch stepping towards the "pitch" man/coach.
Knee drill
Two quarterbacks start with their right knees on the ground, facing each other ten yards apart. One quarterback has a ball on the ground next to his right leg. The quarterback picks up the ball with his power hand, puts the ball to his ear with his off- hand also on the ball and throws it to his partner quarterback across from him. The partner QB catches the ball, places it on the ground and does exactly the same thing throwing the ball back.
Quarterbacks continue playing catch in this manner while the coach helps them with the finer points of their throwing techniques: leading with the throwing elbow, ball at ear and pointing first with wrist and then index finger upon release of the ball.
3/5 Step drop and wave drill
Two quarterbacks start (one with a ball) facing each other 15 yards apart. The coach stands about seven yards from the quarterback with the ball. Quarterback with the ball faces the coach in an "under center" position.
The coach gives a command and the quarterback executes a three- step drop with his feet "chopping/firing" on his third plant step. The coach then gives visual directions with his hands (such as improving quarterback focus by keeping eyes forward) and the quarterback executes a wave drill moving right, left, forward and back.