Joab's brother Abishai was the leader of the Thirty Warriors, and in one battle he killed three hundred men with his spear. He was as famous as the Three Warriors
When the Ammonite soldiers saw that the Arameans had run away, they ran from Abishai's soldiers and went back into their own city. Joab stopped fighting the Ammonites and returned to Jerusalem.
He sent out one third of his army under the command of Joab, another third under the command of Abishai the son of Zeruiah, and the rest under the command of Ittai from Gath. He told the soldiers, “I'm going into battle with you.”
Amasa did not see the dagger in Joab's other hand. Joab stuck it in Amasa's stomach, and his insides spilt out on the ground. Joab only struck him once, but Amasa was dying. Joab and his brother Abishai went off to chase Sheba.
and certainly just as famous as the rest of the Thirty Warriors. He was the commander of the Thirty Warriors, but he still did not become one of the Three Warriors.