Place 2 sausages perpendicular from eachother in a T shape.
Have one player line up a couple meters away from the bag.
Conditioning drill, the player does reps of clearing the bag, running back to the line, doing a down up and going again.
Rebounding is the least glamorous thing in basketball and one of the most decisive. It is also almost entirely a habit, which means it is entirely coachable.
Good spacing is only the start. The best modern offences teach players to attack the defence's rotations and play in a permanent 4-on-3 - here is how to coach that read.
The ball screen produces almost half of all professional offensive possessions, yet most teams still teach it as a memorised play. The modern approach trains the read - giving players a framework to decide based on what the defence does, not what the coach called.