Phorkys

Φόρκυς Phorkys was a son of Pontus and Gaia.

Phorkydes

Phorkys's monstrous children, and the monsters which they in turn generated, would later test the mettle of the heroes Bellerophon, Perseus, Theseus and especially Herakles, all of whom would win undying fame and honour by ridding the world of such dangerous creatures. Edmund Spenser, in the Faerie Queene, appositely calls Phorkys 'the father of that fatal brood / By whome those old Heroes wonne such fame'. (March 2008, p 39)

Γραῖαι Graiai

There were three: Enyo, Pemphredo and Deino, though Hesiod only mentions the first two.

Γοργών Gorgons

There were three: Stheno, Euryale and Medusa.

Echidna

Her upper body was of a beautiful woman, but her lower half was a speckled snake. She dwelt in a subterranean lair, eating raw flesh. She mated with Typhon to produce a troop of monsters:

Kerberos

Multi-headed dog guarding the Underworld.

Lernaean Hydra

A serpent capable of sprouting new heads.

Chimaira

Three-headed beast (lion at the front; goat at the middle; and the rest, snake).

Orthos

Echidna mated with Orthos or Typhon (it is unclear) to produce these offspring:

Sphinx	Plagued Thebes with her famous riddle.
Nemean Lion	His hide was impervious to weapons.

Ladon

The serpent who guarded the Hesperides' golden apples. Sometimes claimed to be a child of Echidna and Typhon, or of Echidna and Orthos.