A famous footnote in the story of Isaac's miraculous birth, little else is known about the Egyptian slave girl, Hagar.
Hagar was given Abram and his wife, Sarai, and later forced to bear his child when Sarai could not produce the heir that God had promised. Hagar was then labeled as "contemptuous" by her mistress, and after being treated harshly by her, fled from her masters into the wilderness, possibly fearing her unborn baby's life.
It was in her wanderings that Hagar had a life-changing encounter at a well, where the promise of the covenant was revealed to her and where she - a foreigner, woman, salve - became the only one in all sacred texts to name God.
"Hagar" cover art by Sarah Beth Baca, https://www.sarahbethart.com/
"The Well (abridged)" by Rachel Held Evans, http://wildwoodmennonite.org/images/Sermons/2019-03-10_The_Well_Hagar_Monologue.pdf
"Hagar: Midrash and Aggadah" https://jwa.org/encyclopedia/article/hagar-midrash-and-aggadah