Hydra, also known as King Hydra, a many-headed, serpent-like creature that guarded an Underworld entrance beneath Lake Lerna. It was destroyed by Heracles, in his second Labour. Son of Typhon and Echdina.
Lycanthrope, or Werewolf, men that was cursed into an anthropomorphic wolf, the first man to be cursed into a werewolf was Lycaon, king of Arcadia, by offering Zeus human flesh.
Chrysaor, a son of Medusa and Poseidon, sometimes said to be a giant, he was born alongside Pegasus by Perseus slashing their mother's head.
Cyclopes (Elder), three one-eyed giants who forged Zeus' thunderbolt, Hades' cap of invisibility, and Poseidon's storm-raising trident, they and the hekatoncheires were sons of Gaea and Ouranos, but Ouranos horrified with his sons, banished them to the Tartarus. Later rescued by gods at titans war.
Cyclopes (Younger), one-eyed giants, they are the sons of Poseidon and very skilled blacksmiths, but not so much as elder ones.
Polyphemus, a cyclops who briefly captured Odysseus and his men, only to be overcome and blinded by the hero. For this reason, he is blind to this day.
The Gegenees, a tribe of six-armed giants fought by the Argonauts on Bear Mountain in Mysia.
Echidna, a giant monstrous women with upper body of a beautiful nymph, while the lower is a giant serpent, she is the wife of Typhon.
Geryon, a three-bodied giant who dwelt on the red island of Erytheia, son of Chrysaor and the oceanid Calirrhoe.
Gigantes, they are offspring of Gaia and Tartarus to replace the gods.
The Hekatoncheires, the Hundred-Handed Ones, giants with fifty heads gods of violent storms and hurricanes, they defeated the titans at a war after the gods rescuing then from tartarus alongside their brothers, the cyclopes.
Briareus or Aigaion (Βριάρεως), The Vigorous
Cottus (Κόττος), The Furious
Gigges (Γύγης), The Big-Limbed
The Laestrygonians, a tribe of man-eating giants encountered by Odysseus on his travels.
Tityos, a giant slain by Apollo and Artemis when he attempted to violate their mother Leto.
Typhon, a monstrous immortal storm-giant who was defeated and imprisoned by Zeus under Mt. Etna. He is the husband of Echidna, and with her they are known as the "Parents of all monsters".
The dragons of Greek mythology were serpentine monsters. They include the serpent-like Drakons, the marine-dwelling Cetea and the she-monster Dracaenae. Homer describes the dragons with wings and legs.
The Ismenian Dragon, a dragon which guarded the sacred spring of Ares near Thebes; it was slain by Cadmus
Ladon, a serpent-like dragon which guarded the Golden apples of immortality of the Hesperides
Three-Headed Hydra, it's believed as the offspring of the Lernaean Hydra, they are multiple-headed aquatic and very poisonous dragons, like their father, more heads will grow by cutting one off.
Python, a dragon which guarded the oracle of Delphi; it was slain by Apollo.
Drakons ("δράκους" in Greek, "dracones" in Latin) were giant serpents, sometimes possessing multiple heads or able to breathe fire, but most just spit deadly venom.
The Laconian Drakon was one of the most fearsome of all the drakons.
Cetea were sea monsters. They were usually featured in myths of a hero rescuing a sacrificial princess.
The Ethiopian Cetus was a sea monster sent by Poseidon to ravage Ethiopia and devour Andromeda, which was slain by Perseus
The Trojan Cetus was a sea monster that plagued Troy before being slain by Heracles.
Automatons or Colossi, were men, animals and monsters crafted out of metal and made animate in order to perform various tasks. They were created by the divine smith, Hephaestus. The Athenian inventor Daedalus also manufactured automatons.
The Hippoi Kabeirikoi, four bronze horse-shaped automatons crafted by Hephaestus to draw the chariot of the Cabeiri
The Keledones, singing maidens sculpted out of gold by Hephaestus