I have continued on with my research, even though I get negative feedback more than positive. But I am so glad I continued.
I might have found something.
I have begun researching will abstracts for Sampson County (1794-1900) and I believe I have found about six family members, possibly seven from the last slave family in my line. This would be in the early 1800s. I have found who I believe to be my great-great-great grandfather (Daniel Boykin), my great-great-grandmother (Harriett Boykin Ireland), and four of her siblings in these papers. One book (by EE Ross) has a Slave Index. In that Index, in with one slaveholder, I have found the children, including Harriett "Boykin". The family name was Barbery or something like that. I found Daniel under Tobias Boykin, who I also found listed with his father, brother, and son; all having wills.
Now I need to get hold of these wills.
I also looked for unusual names. I have a relative named Amret (Calvin Ireland's sibling, Harriet Boykin Ireland's sister-in-law). I found an Amret listed among the abstracts. I need that will also.
I am feeling hopeful; the search continues...