All those were Jacob’s sons from his wife’s servant, Zilpah. (Zilpah was the maid that Laban had given to his daughter Leah.) There were 16 people in this family.
(Laban gave his maid Zilpah to his daughter to be her maid.)
Zilpah was Leah’s maid. Jacob and Zilpah’s sons were Gad and Asher.
Asher’s sons were Imnah, Ishvah, Isvi, Beriah, and their sister, Serah. Also there were Beriah’s sons, Heber and Malkiel.
Benjamin was also with Jacob. Benjamin was Jacob and Rachel’s son. (Joseph was also Rachel’s son, {but Joseph was already in Egypt}.)
Dan, Naphtali, Gad, Asher.