In Bereishit 27:29, Isaac's Blessing of Jacob contains:
"You shall be a master over your brothers, and your mother's sons shall bow down to you."
Are there any explanations in the literature explaining why the plural was used, or perhaps stories of other brothers not in Tanach? 1st D. Hayamim 1:34 only lists Esau and Israel. Bereishit 25:21-22 makes it look unlikely that Rebekah had more, but perhaps she did?