According to some authorities there are two Varahas. According to others, Varaha appeared during the regime of Svayambhuva & stayed in the water until that of Raivata. Some doubt that this could be possible, but the answer is that everything is possible

Expressions researched:
"Therefore according to some authorities there are two Varāhas. According to others, however, Varāha appeared during the regime of Svāyambhuva Manu and stayed in the water until that of Raivata Manu. Some may doubt that this could be possible, but the answer is that everything is possible"

Srimad-Bhagavatam

SB Canto 8

The fighting, however, took place during the reign of the first Manu, Svāyambhuva. Therefore according to some authorities there are two Varāhas. According to others, however, Varāha appeared during the regime of Svāyambhuva Manu and stayed in the water until that of Raivata Manu. Some may doubt that this could be possible, but the answer is that everything is possible.

SB 8.5.6, Translation and Purport

Although the great activities and transcendental qualities of the Supreme Personality of Godhead's various incarnations are wonderfully described, sometimes we are unable to understand them. Yet everything is possible for Lord Viṣṇu. If one could count the atoms of the universe, then he could count the qualities of the Supreme Personality of Godhead. But no one can count the atoms of the universe, nor can anyone count the transcendental qualities of the Lord.

The Lord's glorious activities referred to in this connection took place after His personal bodyguards Jaya and Vijaya became Daityas, having been cursed by the great sages Sanaka, Sanātana, Sanat-kumāra and Sanandana. Jaya, as Hiraṇyākṣa, had to fight with Varāhadeva, and that same Varāhadeva is mentioned in regard to the Raivata millennium. The fighting, however, took place during the reign of the first Manu, Svāyambhuva. Therefore according to some authorities there are two Varāhas. According to others, however, Varāha appeared during the regime of Svāyambhuva Manu and stayed in the water until that of Raivata Manu. Some may doubt that this could be possible, but the answer is that everything is possible. If one could count the atoms within the universe, one could count the qualities of Lord Viṣṇu. But the atoms of the universe are impossible for anyone to count, and similarly no one can count the transcendental qualities of the Lord.