We just do LOTS of leg swings (laying down and standing up), and what we call hanging "split pulls" - hanging on a bar and lift legs to a split, switch split and a switch side. Also tumble track split jumps, switch sides, straddle and turning jumps.
In the past for little kids I've also done a leap landing on a raised soft mat to a split, and a drill where you hold the gymnast's back leg in a back arabesque, and they have to jump and lift their front leg by themselves, and vice versa.
Hope that all made sense. What do you guys do for leaps?