Broadly speaking, there are nine different types of angels. The angels who “abandoned their estate” and commingled with females were from a class called the “Watcher Angels.” Their dwelling place is on earth far removed from the throne of God as compared to the seraphim and cherubim.
Watcher angels take a particular interest in the earthly affairs of human beings, “watching” them, and, at times, even interfering in or controlling situations that concern people. God isolated all the fallen watcher angels who had the inclination to physically mate with humans and has held them up in chains awaiting judgement.
If you want to know more about angels, listen to this fascinating podcast.