Duryodhana is listing the heavyweights of the Pandava side. Yuyudhana (also known as Satyaki) was a powerful Yadava warrior and Krishna’s disciple. Virata was the king who sheltered the Pandavas during their exile. Drupada was the king of Panchala. By naming them, Duryodhana is reminding Drona of the caliber of the men he must kill, attempting to provoke a 'kill or be killed' instinct in his teacher.