In my world witchcraft tends to run in families, mostly along the female line, but not exclusively so. I also have a Tradition of witchcraft known as a Family Tradition. I thought it might be nice to detail some of the families in my games.
To start I have three major witch families with a fourth as a mystery.
Winters
The Winter family is very, very old. So old in fact that many people believe that the season was named for them. As their name implies their magic comes from the use and application of cold.
In this family only the women can become witches. Once a girl in the family turns 13 her hair will turn white and this is the sign that she must travel north to train with the ancient Grandmother Winters. The girls return to the family a year and a day later with the basic knowledge of their family witchcraft. Once returned they will continue their training with other women in their family. Each year they all congregate at a location determined by Grandmother Winters, usually one of the larger homes of the family. The family gathers to begin their celebrations on the Winter Solstice, the height of their power.
The family is common in the northern, colder climes. They own lots of land, but their homes tend to be more primitive than the local homes. Longhouses are most common. Women are almost exclusively witches, with the occasional priest or even wizard. Men tend be barbarians, warriors or occasional bard. They are masters of survival in the cold. Witches gain the Chill Touch spell for free.
Dark Secrets: The Winters Clan often are associated with darker, colder gods like Chernobog. Their men are often accused of lycanthropy, mostly as werewolves.
Clan leader: Grandmother Winters
Current PC: Tanith Winters
Mont Blanc
The Mont Blanc family is also very old. The claim is they came down from a mountain that had been blessed (or cursed) by their gods. The Mont Blanc family on the surface is a rich, philanthropic family. They have married into royal families across the lands and many heads of state can claim at least partial relationship to the Mont Blancs. Not all members have the power of witchcraft, but there is a core family of the "purest blood" that all members are powerful witches, male and female alike.
Theirs in an ancient form of witchcraft passed down through the generations.
What isn't in doubt about the family is that they are rich beyond most kings and queens and likely more powerful. The current family patriarch is Pierce Mont Blanc, an 80-year-old witch of great power and formidable personality. Though the power is shifting to the young twins Kimbra & Kelleigh. Their gathering time is Walpurgis Night, the eve of May.
Dark Secrets: The family is the center of dozens of rumors, each darker than the last. They are believed to worship, even consort with demons. It is also rumored that they also possess the largest collection of occult books and artifacts in the world. It is claimed, in more hushed tones, that the family practices selective breeding in their own ranks. Marrying young women off to older men for their fortunes if they have no ability for the craft, or inbreeding those that do show signs to concentrate the power their blood.
Clan leader: Pierce Mont Blanc
Current PCs: Kimbra & Kelleigh, and Katherine Mont Blanc
Caliban
The Caliban family is cursed, so it is said. They believe to have come from a near human monster that spawned a race of witches known as the Witchbreed. Unlike the Mont Blancs and the Winters, the Caliban have no lands and no wealth to call they're own. What they lack in wealth though they make up for in numbers.
While many of the members of the Caliban family can be monsters to look at, each is also well spoken, eloquent and highly intelligent. They are often accused of being monsters, and some have embraced that role. Some though instead prefer to remain outside of society and away from those that would do them harm.
They appear to be leaderless, but there is a rumor of an ancient hag named Sycorax that rules over them and can call them to her. It is believed they all gather together on Mid-Summer's eve.
Clan leader: Sycorax, mother of Caliban and all his offspring.
There are other, lesser families, in my world as well.
There is a rumor of a fourth large clan, the Gwyddonod, but they were destroyed by the other three.