If you mean true *anaerobic* speed endurance (as opposed to the "stamina" that's necessary to maintain a high *aerobic* steady state):
Research (30 or 40 years old, now) has indicated that the best method to develop speed endurance is change-of-pace running, particularly with multiple speed changes in each repetition.
One example (of many potential drills): 200m with 40m sprint, 40m float, 40 spr, 40 fl, 40 spr. The "float" is not an active deceleration, but just letting momentum carry you. Analogy with driving a car: "sprint" is flooring the gas pedal, "float" is taking your foot off the gas but not touching the brake.