I only have a few Cox entries in my compilation but they may be useful to you someday:
Alice Cox - She became Alice Cox Cook, wife of D. Cook, mother of Thelma Berger (look at Thelma's death certificate!!) Alice Cox was b. in Montgomery, Fayette County.
Annie Cox - See African American Residents of Pocahontas County by William O. Lindsey (Allegheny Historical Society booklet)
Bessie Cox - See Bessie Cox Randall, wife of Richard Randall, mother of Georgianna P. Randall
Catherine Cox - See Catherine Cox Sadler, wife of Thomas Sadler
John cox - 1850 Census, Virginia, Monroe County, Mulatto Male, 4, Free Inhabitant, with the Hennen family.
(If any of the above look like they might belong to you, let me know & I'll look up their information under their married names)