Sects and Rishis

Due to the diversity in religious and cultural traditions and practices, and the Vedic schools which they belong to, Brahmins are further divided into various subcastes. During the sutra period, roughly between 1000 BCE to 200 BCE, Brahmins became divided into various Shakhas (branches), based on the adoption of different Vedas and different rescension Vedas. Sects for different denominations of the same branch of the Vedas were formed, under the leadership of distinguished teachers among Brahmins.
There are several Brahmin law givers, such as Angirasa, Apasthambha, Atri, Bhrigu, Brihaspati, Boudhayana, Daksha, Gautama, Harita, Katyayana, Likhita, Manu, Parasara, Samvarta, Shankha, Shatatapa, Ushanasa, Vashista, Vishnu, Vyasa, Yajnavalkya and Yama. These twenty-one rishis were the propounders of Smritis. The oldest among these smritis are Apastamba, Baudhayana, Gautama, and Vashista Sutras

Descendants of the Brahmins

Many Indians and non-Indians claim descent from the Vedic Rishis of both Brahmin and non-Brahmin descent. For example, the Dash and Nagas are said to be the descendants of Kashyapa Muni.
Vishwakarmas are the descendants of Pancha Rishis or Brahmarishies. According to Yajurveda and Brahmanda purana, they are Sanagha, Sanathana, Abhuvanasa, Prajnasa, and Suparnasa. The Kani tribe of South India claim to descend from Agastya Muni.
The Gondhali, Kanet, Bhot, Lohar, Dagi, and Hessis claim to be from Renuka Devi.
The Kasi Kapadi Sudras claim to originate from the Brahmin Sukradeva. Their duty was to transfer water to the sacred city of Kashi.
Dadheech Brahmins/dayama Brahmin trace their roots from Dadhichi Rishi. Many Jat clans claim to descend from Dadhichi Rishi while the Dudi Jats claim to be in the linear of Duda Rishi.
Lord Buddha was a descendant of Angirasa through Gautama. There too were Kshatriyas of other clans to whom members descend from Angirasa, to fulfill a childless king's wish.
The backward-caste Matangs claim to descend from Matang Muni, who became a Brahmin by his karma.
According to one legend, the nomadic tribe of Kerala, the Kakkarissi, are derived from the mouth of Garuda, the vehicle of Lord Vishnu, and came out a Brahmin.
historian Udai Narain Roy endorses the suggestion that the imperial Guptas were Brahmins.