There are a total of fifteen Zombie types in Resident Evil 0.
Conductor Zombie (車掌ゾンビ Shashō zonbi ) is a special type of Zombie encountered in Resident Evil 0. He is the Ecliptic Express's conductor, who has been infected with Marcus' t-Virus by leeches. If not killed, he will follow player to different rooms.
Executive candidate Zombie
Hazmat Zombies (防護服ゾンビ Bōgo-fuku zonbi ) appears in the Umbrella Research Center complex. They are wearing protective clothing intended to prevent being infected by the t-Virus. They come in versions "A" and "B".
Naked Zombies (裸ゾンビ hadaka zonbi ) are Zombies who were experimented on as an Umbrella research project. As they are found in the treatment plant, they may have been dumped there.
Passenger Zombies (乗客ゾンビ Jōkyaku zonbi ) are a type of Zombie encountered in Resident Evil 0. They are zombified Umbrella employees who were attacked by Dr. Marcus' leeches and infected with the t-Virus. Passenger Zombie appear in two subtypes, known as "A" and "B".
Special Forces Zombie
Special Forces Zombies (特殊部隊ゾンビ Tokushu butai zonbi ) are zombified members of Umbrella's investigation teams sent to the training school. They appear in the first four stages of Resident Evil 0, but don't appear in the Factory or Treatment Plant. They come in three forms: "A", "B" and "C"; "A" is USS Delta Team which appears on the train, while the latter two are the investigation teams sent to the training center.
The Worker Zombies (作業員ゾンビ Sagyō-in zonbi ) are ordinary Umbrella employees, working at the treatment plant when they were infected. They appear in "A" and "B" subtypes.