- Aethon – One of the immortal fire-breathing horses that pulled the chariot of Helios across the sky each day.
- Caucasian Eagle – The giant eagle sent by Zeus to devour Prometheus’s regenerating liver each day as eternal punishment.
- Cetus – A gigantic sea monster sent by Poseidon to ravage the kingdom of Aethiopia before being slain by Perseus.
- The Calydonian Boar – An enormous supernatural boar sent by Artemis to devastate Calydon, but it was purely a monstrous boar rather than a hybrid.
- Cretan Bull – A magnificent but savage bull sent by Poseidon that rampaged across Crete before being captured alive by Heracles.
- Echidna – A half-woman, half-serpent creature known as the “Mother of Monsters” because she birthed many famous beasts.
- Empusa – A shapeshifting female demon that lured travelers before feeding on their flesh or blood.
- Erinyes (Furies) – Fearsome chthonic spirits who relentlessly pursued and punished those guilty of grave crimes such as murder and oath-breaking.
- Golden Ram – A divine flying ram with golden fleece that rescued Phrixus and became the source of the legendary Golden Fleece.
- Griffin (Gryphon) – A majestic creature with the body of a lion and the head and wings of an eagle, revered as a guardian of treasure and sacred places.
- Hippalectryon – A bizarre hybrid creature with the front half of a horse and the rear half of a rooster, commonly depicted on ancient Greek pottery.
- Ichthyocentaur – A marine hybrid with a human torso, horse forelegs, and a fish’s tail, associated with sea deities.
- Khalkotauroi (Colchian Bulls) – A pair of enormous bronze-hoofed, fire-breathing bulls that Jason was required to yoke as part of his quest for the Golden Fleece.
- Ladon – A never-sleeping dragon that coiled around and protected the golden apples in the Garden of the Hesperides.
- Mares of Diomedes – Four savage, man-eating horses owned by King Diomedes that were eventually subdued by Heracles during one of his Twelve Labors.
- Onocentaur – A rare hybrid creature with the upper body of a human and the lower body of a donkey, symbolizing humanity’s conflicting civilized and wild instincts.
- Ophiotaurus – A unique creature with the front of a bull and the tail of a serpent whose entrails were said to grant cosmic power if sacrificed.
- Orthrus – A two-headed dog that guarded the cattle of the giant Geryon before being slain by Heracles.
- Pygmies – A legendary race of tiny humans famous for their perpetual battles against migrating cranes.
- Python – An enormous serpent that guarded the sanctuary at Delphi until it was slain by the young Apollo, who claimed the site as his sacred oracle.
- Telchines – Mysterious sea-dwelling craftsmen and magicians from Rhodes who were credited with forging divine artifacts.
- Typhon – A colossal serpentine monster whose battle with Zeus determined the supremacy of the Olympian gods.
- Other (please specify)
I tried to include a variety, and avoid adding ones that are too similar to each other or to what we already have. What special abilities would you want them to have?
For me: Classical Age: Ophiotaurus- Special attack is to strangle/ constrict (snare/ stun) a unit with a channelled attack. The bull will keep constricting the victim until (making them lose HPs each tick) until the unit dies or enough damage is done to the bull (like a conditional shield) to get it to let go.
Heroic: The Calydonian Boar- Has a charge special attack that skewers enemies on its tusks and causes them to bleed. In addition, it has a passive of doing additional damage/ RoF when near a farm (auto boost)
Mythic: Echidna- Gives birth to monstrous children as she fights. Could be one unique MUs to summon (such as a Orthrus) or could be a randomised pool (like Shennong) of Orthrus, Hydra, Nemean Lion, Caucasian Eagle, Medusa etc.
Mythic Age God Power: Typhon- mini Titan 
P.S. Do you think they could add Caucasian Eagle as a creature?