Naiads: The spirits of the springs
The Naiads, probably daughters of sea god Poseidon, were nymphs who presided over fountains, springs and streams. The Naiads were neither river goddesses nor ancient spirits that inhabited the still waters of marshes. Their spirits however were bound to their springs, so if the spring dried the Naiad would die as well.
Naiads were linked with fresh water lakes the same way as the Oceanids were linked with saltwater and Nereids with the Mediterranean, but since all waters were connected, they were related to some extent in the eyes of ancient Greeks.
Naiads were dangerous and treacherous and were often known to exhibit jealous tendencies towards men. Notably Hylas the legendary argonaught was lost when Naiads seduced him and carried him away fascinated by his beauty.
They were worshipped by humans and youth at coming-of-age ceremonies used to dedicate their childish locks to the naiad of the local spring and many of them were attributed magical or healing powers.
Horae: The wielders of time and seasons
Hyades: With sorrow came rain
In Greek mythology the Horae were the three daughters of Zeus and Themis, Eunomia, Diké, and Eirene, who were law-and-order goddesses.
Moirae: The wielders of fate
The Hyades were the daughters of Atlas and or Aethra, and sisters to the Pleiades and the Hesperides. They were a sisterhood of nine nymphs responsible for bringing rain.
Morpheus: Even gods need to dream
The Moirae in Greek mythology are the personifications of destiny. Same as the Charites and the Hesperides, they were three, Clotho, Atropos and Laxesis. They controlled the thread of life of every mortal from birth to the end.
Oceanids: Three thousand sisters
Morpheus is the son of Nyx, the primordial goddess of the Night. He is the god of dreams, the older and master of the Oneiroi.
The Oceanids were the daughters of the Titans Oceanus and Tethys. They were plenty in number, too many to be counted. Each of the three thousand daughters was the patroness of a spring, lake, pond, pasture, or flower.