Ask most people to describe a zombie, and they'll likely describe something like the creatures from "The Walking Dead": shambling corpses in an advanced state of decay, obsessed with eating live humans, and capable of turning live people into the undead with a single bite.
But not all zombies are like these traditional monsters. Here are some examples of TV shows that feature unique, creative takes on the classic zombie formula.
The White Walkers live to the north of the Wall, and have a truly disturbing power: They can turn any dead body into a "wight." These wights can then be used as an army of the undead. In the Season 2 finale, an entire army of wights faces off against the Night's Watch. Wights can't be killed with normal weapons but can be killed with fire. This is why the Wildlings always burn their dead.
Various episodes of "Doctor Who" deal with zombie-like creatures. In "The Unquiet Dead," the Doctor, Rose, and Charles Dickens face off against corpses that have been reanimated by gas-based alien lifeforms from another dimension. In the two-parter "The Empty Child"/"The Doctor Dances," the "zombies" are braindead humans who have had their genetics rewritten by rogue nanobots.
In one memorable episode of "Sliders," the travelers visit an alternate Earth where the entire planet is facing a unique kind of zombie apocalypse. A pharmaceutical company called Geni-Trax created a weight loss drug called Lipron. Most prescription drugs have some side nasty effects, but Lipron's side effect was pretty extreme. It burned fat so quickly that users felt compelled to eat human fat in order to keep their metabolisms working. The Lipron sickness could be transferred from person to person by a bite, and victims would turn pale and lose the ability to speak coherently.
The Borg may not look like typical zombies, but they are very similar to the undead in many ways. The Borg shamble around after having their humanity removed, violently attack humans as a means of adding to their ranks, their flesh has a rotted/dead appearance, and they rarely use weapons in hand-to-hand combat. There is a cure for this type of space zombie sickness: Both Jean-Luc Picard and Seven of Nine were able to be extracted from the Borg collective and live out relatively normal lives afterward.