Bilhah has two sons
Bilhah had Dan and Naphtali.
Key passages
Ge 30:5–8

And Bilhah conceived and gave birth to a son for Jacob. Then Rachel said, “God has judged me, and has also heard my voice, and has given me a son.” Therefore she called his name Dan. And Bilhah, Rachel’s female slave, conceived again and bore a second son to Jacob. And Rachel said, “I have struggled …

See also
Ge 35:25; 1 Ch 2:2;