Are there only three named angels, or is there a fourth?

There are far more angels than just Michael, Raphael, and Gabriel, but those three are the only ones named in the canonical books that were inspired by the Holy Spirit, so those we can be certain of. Other angels are named in books that are not canonical. The Book of Enoch, which is mentioned by Jude but is not inspired, lists 200 angels with names, and among them is one named Phanuel, notice how it ends in el, which is God, as many Hebrew names do. Phanuel is mentioned together with Gabriel, Michael, and Raphael in the Book of Enoch, and the fact that Enoch already knows the three canonical angels gives some credibility to Phanuel being part of that group of four. Other non-canonical books also name angels: the Apocalypse of Ezra names Uriel and others, the Apocalypse of Abraham names Yahoel, and the Byzantine Catholic and Eastern Orthodox traditions name Barachiel. There is even one in the Apocalypse of Peter named Temeluchus, said to be the angel of aborted or murdered infants, which fits what Jesus says, that their angels always behold the face of My Father in heaven. So there are many more angels with names than the three in inspired Scripture, but you have to be careful, because most of these come from books that are not inspired.