Players all line up behind each other and face the hoop/backboard. They must run up and throw the ball off the backboard and the next person must do the same without touching the ground. (alley oop rebounding). They must continue through the line until they reach the 21st pass and that person must put the lay-up in.
Four players standing still make every ball handler's job harder. Teach V-cuts, L-cuts and back cuts so your team gets open and punishes defenders who overplay.
Good team defence is five players guarding the ball, not five separate one-on-ones. The shell drill is where that starts, so here is how to teach help-side positioning and rotations from the first week of the season.
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.