Who are the remainder of the seven archangels?

They are the archangels Sedakiel, Sarathiel, and Ananiel. In the doxology for all the heavenly beings, we sing, “Seven archangels, praising as they stand, before the Pantocrator, serving the hidden Mystery. Michael is the first, Gabriel is the second, Raphael is the third, a symbol of the Trinity; Suriel, Sedakiel, Sarathiel, and Ananiel; the great and holy luminaries, entreating Him for the creation. The cherubim and the seraphim, the thrones, dominions, and powers; the four incorporeal creatures, carrying the throne of God; the twenty-four presbyters, in the church of the first-born, praising Him without ceasing, proclaiming and saying: Holy God, heal the sick; Holy Mighty O Lord repose those who are asleep. Holy Immortal, bless your inheritance, may Your mercy and peace be a fortress to Your people. Holy, Holy, Holy, O Lord of hosts, heaven and earth are full of Your glory and honor. And when they say Alleluia, the heavenly respond saying: Holy. Amen. Alleluia. Glory be to our God. Intercede on our behalf, O angelic armies and heavenly orders, that He may forgive us our sins.”