There were two generations of Horae: (note: this does not refer to generation in the traditional sense of the second group being offspring of the first; earlier writers recognized the first generation and later authors subscribed to the second.)
The first generation consisted of Thallo, Auxo, and Carpo, who were the goddesses of the seasons (the Greeks only recognized spring, summer and winter). In art, the first generation were usually portrayed as young, attractive women surrounded by colourful flowers, and abundant vegetation, or other symbols of fertility. They were worshipped primarily amongst rural farmers throughout Greece.
Thallo (or Thalatte) was the goddess of spring, buds and blooms, the bringer of flowers, and became a protector of youth.
Auxo (or Auxesia) is Greek for increaser (as in "plant growth"), and she was worshipped alongside Hegemone in Athens as one of their two Charites.
Carpo (or Xarpo) was in charge of autumn, ripening, and harvesting, as well as guarding the way to Mount Olympus and letting back the clouds surrounding the mountain if one of the gods left. She was an attendant to Persephone, Aphrodite and Hera, and was also associated with Dionysus, Apollo and Pan.
The second generation comprised Eunomia, Dike and Eirene, who were law and order goddesses who maintained the stability of society. They were worshipped primarily in the cities of Athens, Argos and Olympia.
Dike (Greek for justice) was the goddess of moral justice. She ruled over human justice; her mother (Themis) ruled over divine justice. Dike was born a mortal and Zeus placed her on earth to keep mankind just. He quickly learned this was impossible and placed her next to him on Olympus.
Eunomia (Greek for good order) was the goddess of law and legislation. The same or a different goddess may have been a daughter of Hermes and Aphrodite.
Eirene or Irene (Greek for peace) (the Roman equivalent was Pax) was the personification of peace and wealth, and was depicted in art as a beautiful young woman carrying a cornucopia, scepter and a torch or rhyton.
The Horae with wedding presents for Peleus, Louvre Museum
The Horae, Relief
Some authors recognise yet a third set of Horae. They were Pherusa (or Pherousa, goddess of substance and farm estates), Euporia (or Euporie, goddess of abundance), and Orthosie (goddess of prosperity).
Finally, there are the twelve hours (originally only ten), tutelary goddesses of the time of day. The hours run from just before sunrise to just after sunset:
Auge, first light
Anatole or Anatolia, sunrise
Mousika or Musica, the morning hour of music and study
Gymnastika, Gymnastica or Gymnasia, the morning hour of gymnastics/exercise
Nymphe, the morning hour of ablutions (bathing, washing)
Sponde, libations poured after lunch
Elete, prayer, the first of the afternoon work hours
Akte, Acte or Cypris, eating and pleasure, the second of the afternoon work hours
Arktos, last light
The Horae in Guido Reni's Aurora dancing around Apollo