Hybrid

Even though most of the time vampire-werewolf hybrids are referred to as "hybrid", hybrids of other species were seen too throughout the fanfictions. Most notable hybrids are listed on this page.

Vampire-werewolf Hybrid
The method to create these hybrids are turning werewolves into vampires. Process requires blood from the original hybrid Klaus to turn the werewolf, and blood from the doppelganger to complete the transition successfully.

The only known vampire-werewolf hybrid that didn't turn with Klaus' blood was Klaus himself, who still needed blood from the original doppelganger, Tatia, to survive his transition.

Other vampire-werewolf hybrid in the series was Tyler Lockwood.

Werewolf-witch Hybrid
This type of hybrid can only be born, as witchcraft and the werewolf curse can only be taken through bloodline. Typically, one parent has to be a werewolf, while the other has to be a witch.

Although it is possible that this type of hybrids are plenty, only known one is Klaus, before he was turned into a vampire and lost his witch abilities.

Vampire-witch Hybrid
This type of hybrid was introduced in the second season of Stefan's Diaries.

Typically, when a witch becomes a vampire, they lose their witch side. It was explicitly stated that one can only be a witch or a vampire, but never both. However, a powerful witch called Isla Kennedy managed to brake this rule by using dark magic and blood from the doppelganger, Katherine Pierce.

By using the cure in Katherine's blood, Isla tricked her spirit into thinking it was still a witch, while the rest of her body acted as a vampire. This allowed her to keep her witch powers, making her the first and only vampire-witch hybrid in history.

This type of hybrid possesses all witch and vampire abilities, including immortality.

Vampire-werewolf-witch Hybrid
Also known as the "Tribrid", this type of hybrid is virtually impossible to create. However, Klaus, a former witch and vampire-werewolf hybrid, somehow impregnated Hayley, a werewolf, which allowed the birth of a tribrid child, Hayden Mikaelson, who possesses vampire, werewolf and witch abilities.

Even though Hayden's aging only allows her to have limited access to her vampire powers, such as limited speed, strength, healing, mind compulsion, etc., she is still too strong and fast for a normal human.

Post Season 3 Series
It was stated that when an original vampire dies, every vampire that turned in their bloodline dies along with them. This is because the magic that keeps a vampire (who essentially is a dead person) alive comes from the first of the vampires, who were created by and therefore are the sources of this magic.

Early in the series, Rebekah, Elijah and Kol were killed, causing the deaths of 3/4 of the world's vampire population.

Finally, when the last original vampire Klaus was killed in the series finale, the rest of the vampires also died the following hour. Additionally, Samara destroyed the instructions of creating original vampires, ending the species once and for all.

Stefan's Diaries
In the sixth season of the series, the supernatural world faces imminent extinction due to a spell that is cast by Ewa. Realizing there is no way to stop or contain the spell that would kill every supernatural species in the world, for survival, witch covens from all around the world joined forces and destroyed the magic on the planet. This turned everything supernatural into humans, effectively causing the absolute extinction of every supernatural species, including hybrids.