8, Israelites, Keturah, Midian
A list of Abraham’s sons (and their sons): Genesis 25 and parts of Chronicles
Abraham remarried after Sarah died, giving him six more children:
Genesis 25:2 She gave birth to Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah.
One of them, Midian, was the ancestor of the Midianites, who later became an existential threat to the Israelites.