Concept and creation
Pure-blood wizards claim to have no Muggle blood at all in their genealogical pedigree. In response to fan questions, Rowling has said that to be considered pure-blood, all of one's grandparents must have been wizards: some of the more severe schools of thought may require several more generations of wizards to be considered pure-blood. She has also said that true pure-blood wizards do not exist in the Harry Potter universe (if they ever did exist in the past), and that they merely erase Muggles and Squibs off their family trees.

Pure-blood

Pure-blooded families
Most of the members of The Noble and Most Ancient House of Black were advocates of blood purity, and many were involved with the Dark Arts. The Black family home at Number Twelve, Grimmauld Place, London, contains many artifacts of dubious origin and/or dangerous ability
Andromeda Black, cousin of Sirius, was disowned for marrying "Muggle-Born Ted Tonks" (who had in Order of the Phoenix been said by his daughter Nymphadora to have been a Muggle-born wizard). The Black family
The Crouch family figures prominently in the plot of Harry Potter and the Goblet of Fire. They are a once-great and respected family of wizards

The Crouch family

Main article: The House of Gaunt The House of Gaunt
The Lestrange family consisted of Rodolphus, his wife Bellatrix (née Black), and his brother Rabastan.

The Lestrange family
Known living members of the Longbottom family include Neville Longbottom, his grandmother Augusta, and his parents, Frank and Alice Longbottom, who are both mentally incapacitated from being tortured by Bellatrix Lestrange. Frank and Alice are in a special ward for permanent residents at St. Mungo's Hospital for Magical Maladies and Injuries.
The Longbottoms are not as poor as the Weasleys: Cedrella Black was disowned for marrying Septimus Weasley, but her sister Callidora, who married Harfang Longbottom, remains on the Black family tapestry.

The Longbottom family
The Malfoy family is one of the last In the epilogue of the final book, it is revealed that Draco has a son named Scorpius.

The Malfoy family
The Potter family was a very wealthy.

The Potter family
Molly Weasley's family, the Prewetts, were also a pure-blood family.

The Prewett family

Main article: Weasley family The Weasley family
Half-blood wizards are not Muggle-born, but their heritage includes one or more Muggle ancestors. Half-bloods are the most common kind of wizard (Rowling has stated that of the Hogwarts annual intake, 50% are half-bloods.
While Lord Voldemort is a half-blood, he desires blood purity in the wizarding world.

Half-blood
Some half-bloods are products of unions between human wizards and magical beings

Muggle-born
A Squib is a person of wizarding heritage who lacks magical ability;.