1. Bhagadatta : Who owned Vaishnavastra and no one defeated him except Arjuna. He was one of the terrific warrior with his elephant Saupatrika . He was killed by Arjuna after he used Vaishnavastra .
2 . Dronacharya : Even though he couldn’t capture Yudhishtira he was one of the strongest warrior in Kaurava side . Where he formed Chakravyuha in his commander ship and also Maha vyuha combining 3 vyuhas which is very difficult to maintain . And even he was the only man other than Bhurishrava who got killed unfairly in mahabharatha
3. Ashwathamma : He was one of the bad ass warrior in Kaurava side . He used Narayanaasthra which was about finish the war . And powerful Agneyasthra which made one Akshouni died with that single asthra . He was the one who defeated Ghatodgaja army single handedly when his army was fleeing
4. Bhishma : Even Bishma was powerful and he was 2 maharathi . Even he had a boon of icha mruthyu. He was unable to kill by anyone. Killing 10000 soldiers a day. And he was the one who used first brahmastra in mahabharatha against Virata son . At finally he only said about his death secret. Otherwise killing Bhishma would have become tough challenge for pandavas
5. Karna : He was considered one of the strongest warrior on Kaurava side. He defeated multiple maharathi on the 17 the day . Even his last fight was mentionable against Arjuna where he countered brahmastra with normal arrows and cutting the bow string of Gandiva .
Even he defeated Yudhishtira and left him to flee . But it was Karna’ s foolishness that he might have captured him and finished the war , as he gave promise to Kunti not to kill other pandavas except Arjuna. But on the other hand I think this is a later addition of mahabharatha where allowing king to flee is not a believing one
5. Krithavarma : Even though he couldn’t defeat Sathyaki , Arjuna and Ashwathamma he defeated all the major warriors in pandavas side . Countering group attack on 14th day with more than 10 warriors is really great feat of Krithavarma . He was also one of the survivor of kurukshetra war
6. Shalya : He was the one who first killed major warrior of pandavas ‘ Uthara Kumara’ . He also made draw with Bhima in made fight. He was also commander on last day of kurukshetra war