Newton Earp (Nicholas' eldest son by a previous marriage) and his wife Nancy had five children:  Effie May, Wyatt Clyde, Mary Elizabeth, Alice Abigail and Virgil Edwin.

Adelia Earp (Wyatt's youngest sister) and her husband William Edwards had three children:  Nicholas, Estelle Josphine and Mary Virginia.

Virgil Earp had daughter Nellie Jane with his first wife Magdalena ("Ellen") prior to his enlistment in the Civil War.

James Earp and his wife Bessie may have had a son named Frank, but records confirming this are sketchy.  The 1880 census of Tombstone lists a daughter, Hattie, who likely was James' 16 or 17 year old stepdaughter, but there is no mention of Frank, who would have been about six at that time.

There are many living descendants.  A search of the web's genealogy sites will turn up quite a few.