Haitian Voodoo Zombies
There were certainly other zombie films out there before George Romero introduced us to the living dead. The most well-known of these was perhaps 1932's "White Zombie," which featured Bela Lugosi as a Haitian voodoo master, which made sense to moviegoers at the time. In that film, a zombie is created through evil spell casting, and when the antagonist is vanquished, his zombie is awakened from their coma.
Even Romero recognized the difference between a Romero zombie and what some could refer to as a voodoo zombie. Since he believed he had produced ghouls and zombies were things from voodoo belief, he actually avoided using the name "zombie" in his first film. In that system, a voodoo practitioner known as a boko or bokor is capable of severing the soul from the body to produce a zombie. This is more of an automaton, a slave that does the will of the bokor and can even be utilized for good rather than a carnivorous monster.
Wade Davis, an ethnobotanist, asserted in 1983 that he had discovered the toxicological explanation for voodoo zombies, abandoning the magical one. His study was then challenged for being unscientific, which may have added to the enigma surrounding the concept of what a voodoo zombie would be and whether or not they were real.