The Gaunt family

Everyone knows that the Gaunts are descended from Salazar Slitherin. But what some don't know is that they are also descended from Cadmus Peverell.

Either Salazar or Cadmus had a-lot-of-greats grandchildren that eventually became Rionach, Germaith, and another unknown Gaunt.
Rionach married William Sayre and together they had Isolt Sayre who married James Steward and together had Martha the second (named after her grandmother on her father's side.) and Rionach.

And the unknown of the three siblings married an unknown witch who gave birth to Corvinus Gaunt who married yet another unknown person, and had Marvolo Gaunt. Marvolo married and had Merope and Morfin Gaunt. Merope married Tom Riddle, a muggle who had Thomas and Mary Riddle as parents. Merope gave birth to Tom Riddle Jr. and you know that he married Bellatrix Lestrange.