BP; Leaps/jumps are difficult. I am reminded of this each day in the gym as the skills have large skill value in the USA G Code of Points. Resistance bands kicks and repeat jumps on Tramp and TT (tumble track) are part of the normal leap complex for many of our gymnasts. Good stuff.
5x5x5's: I regularly include 5x5x5's as a part of warm-ups. (5 thera band strong leg split jumps, 5 other leg split jumps and 5 switch leg jumps). I have the gymnasts do sets of 5x5x5's with different focus. Tight leg lifts (not working on amplitude), tight knee, level hips, foot positions, body shaping, complementary arm movements are some of the focuses I use.
Uphills: Some of our USAG L3-6's are on a unit working on strength for jumps/leaps. We have been working on making a sequence of jumps ending the 2nd jump on an adjacent panel mat. This "uphill" is emphasizing strong take-off and active split. Combinations and even a panel mat mountain have made it interesting and challenging for the gymnasts. It has been working to achieve larger amplitudes and dynamics in the jumps. Next week is planned to have them to do a jump shape and then a split jump and land sitting in the split on a block adjacent to them. I have done this with our optionals with switch jumps and twisting splits and have seen the dynamics and "balance" of the split/switch improve.
Striders: To capitulate on Iwanna's reply I suggest "striders." I stand the big cheese mat against a support beam. I have the gymnasts make a striding step, swinging their lead leg up as high as the straight leg can go up against the mat. The pointed toe of the striding leg is supported by a releve leg that is straight and tight. This drill I have used to drill tight back leg take off and the strong lift. I can also use it to work the complementary body positioning of the leap/jump as I have them hold it for a few seconds.
Scissones; I use these jumps shapes in combo with splits. I find that working them as a separate skill has benefited split leaps. To my thought, it just allows me more opportunity to work the strength, technique and timing of jumps or combos.
I will read with interest what other sage advise is given to your query.
Best, SBG-