Laser Gun Blaster (Zombadings - Patayin sa Shokot si Remington)
Anyone that touches enough of Giselle Gewelle's (Bleach) blood becomes a zombie under her control.
The Black Lantern Corps (DC Comics) is controlled by and in turn zombified by Nekron, the embodiment of the lifeless void. Such zombification can include even those who are alive, but have been resurrected.
Grandfather (Codename: Kids Next Door) can transform anyone he touches into zombies.
Anthony (Eternal Darkness) was transformed into a zombie after he opened a cursed scroll meant for Charlemagne the Frank.
White Walkers (Game of Thrones) can reanimate the dead to do their bidding.
Energy Vampires (Lifeforce) are a shapeshifting alien species that can drain energy from normal living beings...
...turning them into mindless, living corpses...
...which can also suck energy from other humans.
After killing them, Halloween (Marchen Awakens Romance) can use his Darkness ÄRM, Grave Hail to call people from the dead and force them to fight for him.
Anyone who gets resurrected by Curtis (Misfits) will have a craving for eating flesh, whether it be a human like Shannon Speers...
...or an animal such as a cat.
The Mask (Red Dead Redemption Undead Nightmare) is a cursed Aztec artifact that Abraham Reyes stole believing it would make him immortal, but instead turned him into a zombie and reanimated all of the dead in New Austin, West Elizabeth, and Nuevo Paraiso.
A product of the T-Virus (Resident Evil)
As a result of T-virus infection, Marvin Branagh (Resident Evil 2) becomes a zombie.
While it is unknown exactly how it was created and where it came from, SCP-008 - Zombie Plague (SCP Foundation) are cells that can both kill and reanimate sentient life into Zombies.
Walkers (The Walking Dead) transmit primarily through bites.
Zing Zom-Bone (Xiaolin Showdown) can turn anyone into a mindless zombie and make them obey the user.