"So all the incarnations of the Lord are mentioned in the revealed scriptures. There is no scope for an imposter to become an incarnation, for an incarnation must be mentioned in the sastras. An incarnation does not declare Himself to be an incarnation of the Lord, but great sages agree by the symptoms mentioned in the revealed scriptures. The features of the incarnation and the particular type of mission which He has to execute are mentioned in the revealed scriptures.
Apart from the direct incarnations, there are innumerable empowered incarnations. They are also mentioned in the revealed scriptures. Such incarnations are directly as well as indirectly empowered. When they are directly empowered they are called incarnations, but when they are indirectly empowered they are called vibhutis. Directly empowered incarnations are the Kumaras, Narada, Prthu, Sesa, Ananta, etc. As far as vibhutis are concerned, they are very explicitly described in the Bhagavad-gita in the Vibhuti-yoga chapter. And for all these different types of incarnations, the fountainhead is the Garbhodakasayi Visnu."
Srimad-bhagavatam 1:3:5 Purport
"The seven great sages and before them the four other great sages and the Manus [progenitors of mankind] are born out of My mind, and all creatures in these planets descend from them."
"The Lord is giving a genealogical synopsis of the universal population. Brahma is the original creature born out of the energy of the Supreme Lord known as Hiranyagarbha. And from Brahma all the seven great sages, and before them four other great sages, namely Sanaka, Sananda, Sanatana and Sanat-kumara, and the Manus, are manifest. All these twenty-five great sages are known as the patriarchs of the living entities all over the universe. There are innumerable universes and innumerable planets within each universe, and each planet is full of population of different varieties. All of them are born of these twenty-five patriarchs. Brahma underwent penance for one thousand years of the demigods before he realized by the grace of Krsna how to create. Then from Brahma Sanaka, Sananda, Sanatana and Sanat-kumara came out, then Rudra, and then the seven sages, and in this way all the brahmanas and ksatriyas are born out of the energy of the Supreme Personality of Godhead. Brahma is known as Pitamaha, the grandfather, and Krsna is known as the Prapitamaha, the father of the grandfather. That is stated in the Eleventh Chapter of the Bhagavad-gita (11.39)."
Bhagavad-gita 10.6, Text and Purport
Bhaktivedanta Book Trust. HDG A.C. Bhaktivedanta Swami Srila Prabhupada.
While the subject of Lord Krsna's transcendental expansions is inconceivably complex, the following diagram provides a simple view of the hierarchy of incarnations. Single-click on each name below, and a pop-up box will provide more detail.