Maharshi a Rishi who is very great in his spirituality(great seer), who had reached a certain level towards his goal(path).
Rajarshi a King who is so spiritual that he becomes a Rishi.
Devarshi a Rishi dwelling in the heavenly regions or a deva who is also a Rishi. The sons of Dharma or Yoga, divine or godlike sage.
Brahmarshi a Rishi who has seen the Supreme Spiritual Truth and who were the founders of gotras of Brahmans or caste-races.