Hypnos -If he sleeps a lot, meaning sleep. Morpheus works as well, he was the god of dreams.
Pan -If he becomes scared easily, derivation of Panic.
Poseidon -If he is moody and likes water...the last part is rather rare. ^^
Prometheus -This would fit any cat with a wildy rebellious disposition.
Uranus -If he's fixed.
Zeus-If he is spoiled and is treated like a king, or acts like he is the owner and you are the pet sort of relationship. For a very dominant cat.
Adonis-This name is best suited for a vainglorious cat of very, very uncommon handsome looks.
Aeolus-A title that would fit a rambunctious feline that behaves more like a cyclone than a cat. After the god of wind. ^^
Apollo-For a strong and proud cat of extremely noble temperment.
Ares-For a mean-spirited cat.
Argos-In Greek tale, this thing had 100 eyes distributed all over its body so that 50 could stay alert and watchful while the other 50 slept, alternating in shifts. Anyway, if your cat is one of those types that you always notice staring at you when you least expect it, then here's the perfect name.
Atlas-With the connotation of travel buried in this name, it just very well may suit a well traveled kitty, even if that only means well traveled around the neighborhood.
Chronus-A Titan. Since the Titans were giants, I can picture Cronus as an appropriate name for a huge, well-fed cat with a somewhat grouchy attitude.
Dionysus(
Dye'-Eh-Nye'-Sus)-If your cat is perpetually rowdy, then maybe he has a touch of Dionysus in him already.
Eros-Obviously this name would best suit a cat whose personality and nature go far deeper than what is initially apparent. If this cat has a tendency of sneaking up and biting you if you're not careful, this is the name.
Ganymede(Gan'-Ah-Meed)-Nice generic name for a sharp looking cat.
Hades- A name for a dominant black cat.
Helios-For an outdoorsy cat.
Hephaestus(Heh-Fest'-Us)-A perfect name for a skilled and crafty nature.
I'll post more soon.