Rama, Vyasa, Drona's son Ashvatthama, are the other Rishis. These are the great Rishis as divided into seven groups, cach group consisting of seven.
रामो व्यासस्तथा द्रौणिरश्वत्थामा च लोमशः। इत्येते मुनयो दिव्या एकैकः सप्त सप्तधा॥