(in descending order of rank in the angelic hierarchy)
Seraphim (singular ‘seraph’) are described as having six wings; two used to cover their face, two used to cover their feet, and two to fly. They also have a strong association with fire and may therefore be depicted as being on fire.
Cherubim (singular ‘cherub’) have four faces: one of a man, one of an ox, one of a lion, and one of an eagle. They have four conjoined wings, each of which are covered in hundreds of eyes. They have the body of a lion and the feet of an ox, and human hands.
Ophanim (singular ‘ophan’), also known as Thrones, are two adjacent blue-green wheel-within-a-wheels with hundreds of eyes covering their rims. They are also on fire. Ophanim often house the souls of Cherubim, and are therefore usually seen accompanying them.
Dominions, also known as Hashmallim (singular ‘hashmal’) or Lordships, are the only angels described as appearing as beautiful humans with a single pair of wings.
Virtues, then Authorities, come after Dominions, but neither are described in any detail.
Principalities, also known as Rulers, are described as wearing a crown and carrying a scepter of light. Not much description of their physical form is given, however.
Archangels have been frequently depicted as winged humans, but Biblical reactions to their appearances suggest that their real appearance is much more terrifying.
Angels, the lowest and largest class of angel, are described as having immensely varied forms, and so may come in all shapes and sizes,
It’s also worth remembering that most angels, in their true forms, are immensely large, and in some cases it would take several year’s journey on foot to travel from the top to the bottom of one. Also, most angels are quite luminous, and some are outright Lovecraftian in that gazing upon them may lead to blindness or insanity.