In the Brahma-saṁhitā (5.33) we have information of many, many incarnations of the Lord. It is stated there:
advaitam acyutam anādim ananta-rūpam
ādyaṁ purāṇa-puruṣaṁ nava-yauvanaṁ ca
vedeñu durlabham adurlabham ätma-bhaktau
govindam ādi-puruṣaṁ tam ahaṁ bhajāmi
"I worship the Supreme Personality of Godhead, Govinda (Kṛṣṇa), who is the original person—absolute, infallible, without beginning. Although expanded into unlimited forms, He is still the same original, the oldest, and the person always appearing as a fresh youth. Such eternal, blissful, all-knowing forms of the Lord are usually not understood by even the best Vedic scholars, but they are always manifest to pure, unalloyed devotees."
(Bhagavad-Gita----4:5----purport).

There are various kinds of avatāras, such as puruṣāvatāras, guṇāvatāras, līlāvatāras, śakty-āveśa avatāras, manvantara-avatāras and yugāvatāras—all appearing on schedule all over the universe. But Lord Kṛṣṇa is the primeval Lord, the fountainhead of all avatāras. Lord Śrī Kṛṣṇa descends for the specific purpose of mitigating the anxieties of the pure devotees, who are very anxious to see Him in His original Vṛndāvana pastimes. Therefore, the prime purpose of the Kṛṣṇa avatāra is to satisfy His unalloyed devotees.
(Bhagavad-Gita----4:8----purport).

The one Supreme Personality of Godhead is eternally engaged in many, many transcendental forms in relationships with His unalloyed devotees
(Bhagavad-Gita----4:9----purport).

The unalloyed devotees of the Supreme Lord, who are totally surrendered souls, do not care when they leave their bodies or by what method. They leave everything in Kṛṣṇa's hands and so easily and happily return to Godhead. But those who are not unalloyed devotees and who depend instead on such methods of spiritual realization as karma-yoga, jñāna-yoga and haṭha-yoga must leave the body at a suitable time and thereby be assured whether or not they will return to the world of birth and death.
(Bhagavad-Gita----8:23----purport).

The Lord has described in summary the body, knowledge and the knowable. This knowledge is of three things: the knower, the knowable and the process of knowing. Combined, these are called vijñāna, or the science of knowledge. Perfect knowledge can be understood by the unalloyed devotees of the Lord directly. Others are unable to understand.
(Bhagavad-Gita----13:19----purport).

And the powerful Personality of Godhead Śrī Kṛṣṇa can be fully satisfied by such unalloyed devotees free from all sorts of desires for personal benefit.
(Srimad Bhagavatam----1:7:10----purport).

Such unalloyed devotees are distinct from the mixed devotees who approach the Lord for mitigation of miseries and poverty or because of inquisitiveness and speculation.
(Srimad Bhagavatam----1:8:27----purport).

But as far as His unalloyed devotees are concerned, He gives the protection personally.
(Srimad Bhagavatam----1:12:17----purport).

Kṛṣṇa and His unalloyed devotees cannot be separated, and therefore glorifying the devotee means glorifying the Lord and vice versa.
(Srimad Bhagavatam----1:16:13-15----purport).

It is therefore stated here: duratyayaḥ, or, in other words, spiritual happiness in the eternal kingdom of God cannot be imagined even by the great brahmacārīs or sannyāsīs who are eligible to be promoted to the planets beyond the region of heaven. Or, the greatness of the Supreme Lord is so great that it cannot be imagined even by the great brahmacārīs or sannyāsīs, but such happiness is factually attained by the unalloyed devotees of the Lord, by His divine grace.
(Srimad Bhagavatam----2:6:18----purport).

The unalloyed devotees of the Lord know the glories of the Lord in the sense that they can understand how great the Lord is and how great is His expansion of diverse energy.
(Srimad Bhagavatam----2:7:42----purport).

The Lord has unlimited numbers of transcendental qualities, and one of them is His affection for His unalloyed devotee.
(Srimad Bhagavatam----2:9:32----purport).

That is the way of the Lord's mercy towards His pure unalloyed devotees.
(Srimad Bhagavatam----3:3:10----purport).

Great unalloyed devotees of the Lord are compassionate towards the fallen, and therefore they travel all over the world with the mission of bringing souls back to Godhead, back to home.
(Srimad Bhagavatam----3:5:3----purport).

This highest stage of relationship with the Lord can be attained simply by hearing about Him (His name, form, quality, etc.) from authentic sources like Bhagavad-gītā and Śrīmad-Bhāgavatam, recited by pure, unalloyed devotees of the Lord.
(Srimad Bhagavatam----3:9:5----purport).

The Supersoul gives instructions to the sincere, unalloyed devotee on how he can progress more and more in approaching the Supreme Personality of Godhead.
(Srimad Bhagavatam----4:30:20----purport).

The special mercy for the unalloyed devotee is that the Lord saves him from hard labor to achieve the results of religion, economic development and sense gratification.
(Srimad Bhagavatam----6:11:23----purport).

An unalloyed devotee is never disturbed by any kind of trying circumstance.
(Srimad Bhagavatam----6:12:19----purport).

If one becomes an unalloyed devotee of the Supreme Lord, he automatically manifests all good qualities.
(Srimad Bhagavatam----8:3:16----purport).

Śrī Caitanya Mahāprabhu has instructed that an unalloyed devotee should consider himself a servant of the servant of the servant of the Supreme Lord.
(Srimad Bhagavatam----5:24:25----purport).