Kung fu is a very specific form of violence. Grounded in the pacifist, naturalist worldview of Buddhism, it requires discipline, patience and most of all, strength—mentally, to know when to use it, and physically, to act effectively when the time comes. Masters of kung fu tend to be reluctant fighters because they know violence usually begets more of the same.
But ultimately, in the course of human events, there arises a foe so wicked, so unreasonable and so dangerous that the only choice is self-defense. And when the hero makes that choice, they kick wholesale ass. 
Starting in the 1970s and continuing steadily onwards, kung fu has remained an international cinematic interest, giving rise to three main stars. Bruce Lee is the ideal—a man with equal parts intense charisma and blindingly quick movies. Jet Li is the empty vessel—a man with a blandly benevolent personality, but who moves with unrivaled grace and power. And Jackie Chan is the comedian—a man who gets laughs first for his gleeful goofiness, then out of disbelief for the batshit stunts he completes. 
Which brings us to another impressive and important thing about kung fu movies—they combat the American stereotypes long hurled at Asian men that question their manhood, and even further, their humanity. So, in 1972’s The Way of the Dragon, when Bruce Lee snapped the neck of hairy, red-blooded Man, Chuck Norris, that was something brand new to Americans. 
Situated in this context, we’ll judge that film and 24 others by partially considering the main fighter’s technique—from a thoroughly non-expert perspective—as well as their motivations for fighting. So, here’s Complex’s definitive round-up of all those whose kicks were fast as lightning.