Elizabeth Gilman (1747-1790) inherited a "Negro girl Phillis" from her sister, Eunice Sayer Gilman.

In the abstract of the 1775 probate proceeding, it's stated that Eunice Gilman left "to my sister Elizabeth Gilman my Negro girl Phillis & if he be living to my son Ebenezer when he comes of age & if not, then to said sister." - Frost, Vol. II Note: Eunice and her sister Elizabeth both married men named Gilman.

Eunice's Will states: "I give unto my dear Sister Elisabeth Gilman my Negro Girl Phillis to live with Her as a Servant andd to be kept and cloathed [sic] by Her until my son Ebenezer Gilman arrives to Man's Estate and if He should die in Minority or under Age, I give the said Negro girl Phillis to my said sister Elisabeth Gilman to be Hers & her Heirs forever."

Elizabeth married Rev. Tristram Gilman. She is buried in Yarmouth: https://www.findagrave.com/memorial/28464555/elizabeth-gilman

Bibliography:

Maine Probate Abstracts Vol II 1775-1800 - John Eldridge Frost (1991)

York County Registry of Probate