Another great agility drill to add to your workouts is the 4 cone drill/ square drill. Like the Pro Agility, it's a drill that requires little to no equipment. All you really need is a square with enough room for a short sprint. the square drills are great for quick change of direction in a small space.
The beauty of this drill is that there is no right or wrong pattern. You can come up with any movement/patterns that you want to make it unique to each player or just to keep them from getting bored. That being said, I would like to pass on two of my favorites.
1) Set up your cones in a square with room for short sprints between cones (at least 5yds) or find a square on the court. Start at one corner, on go the athlete will sprint to the cone straight ahead, side shuffle to the cone next to it, back pedal from that cone to the one behind then finish with a side shuffle back to the cone you started at (see below). Using the diagram below; Sprint from 1 to 2 -> side shuffle from 2 to 3 -> back pedal from 3 to 4 -> side shuffle from 4 to 1.
                                            2  Side shuffle  3
                                         Sprint                Back Pedal
                                            1  Side Shuffle  4
*To add a bit to that drill simply have the athlete circle every cone when they reach it. (Sprint from 1 to 2 and circle 2 then go into a side shuffle to 3 and circle 3, back pedal to 4 and circle 4, side shuffle to 1 and circle 1)
2) Start at a corner and sprint forward, back pedal back to the cone, sprint diagonal, back pedal back to start, side shuffle sideways to cone and shuffle back to start. Again using the diagram and numbers; Sprint from 1 to 2 -> Back pedal from 2 to 1 -> Sprint from 1 to 3 -> Back pedal from 3 to 1 -> Sude Shuffle from 1 to 4 -> Sude shuffle from 4 to 1.
                                            2                3
                                            1                4
*For safety, remove the starting cone and just imagine it's there. A lot of players will slip on it while back pedaling.