Angel of Obedience - Sraosha in Manicheanism.
Angel of Oblivion - Purah or Puta or Poteh. Reffered to also as the angel of forgetfulness.
Angel of October - Barbiel. In ancient Persian lore, Aban.
Angel of the Odd (fictional) - In Edgar Allen Poe's short story so titled, awingless, Dutch-English speaking angel, more like an automotron, who "presides over the contretemps of mankind." The business of this angel or genius is "to bring about the odd accidents which are continually astonishing the sceptic."
Angel of Omnipotence - There are (or were) 8 angels of this class, Atuesuel, Ebuhuel, Elubatel, Tubatlu, Baulu, Talatu, Labusi, Ublisi. In the Citation of Leviathan, the first 3 angels are involked to force demons to appear and do the bidding of the invocant.
Angel of Oracles - Phaldor.
Angel of Order - Sadriel.
Angel of Orion - In the Alphabet of Rabbi Akiba, the angel of Orion (unnamed) is included among the splendid, terrible and mighty angel chiefs" who passed before God to extol and rejoice in the 1st Sabbath.