Interesting...
Okya so I got bored yesah, but after stumbling across the game master list. I found that Aphrodite, Oceanus and Hyperion all had something to do with Greek Mythology (from what I knew at the time). I then dicided to seacrch the others up, and apart from Coriolis (probably refering to the Coriolis effect), and Equinox (Refering to the Equinox). All had Greek relations in some way or another, I'll post the list later.
Aphrodite - Greek Goddess of Love and Beauty (Greek)
Atropos-Eldest of the Three Fates. (Greek)
Clotho-One of the three fates (Greek)
Coriolis -Non Greek.
Cronus-Derived from Kronos, Lord of the Titans (Greek)
Endymion-King/Hunter/Sheperd. (Greek)
Equinox-Non Greek.
Glaucus-Son of Minos(Greek)
Hyperion- Lord of the Light, Titan of the East, (Greek)
Oceanus-Titan of the Ocean (Greek)
Thalia-One of the three Graces, (Greek)
Mnemosyne-Personification of memory in Greek mythology. (Greek)
And funnly enough, the admin that posted this is list is Poseidon, Greek god of the Sea.

If I was a Greek GM, I would be Dionysus.
It's obvious why, isn't it?

Oh Shoebox, always a character.
Yes, very appropriate choice.
Oh you, you do like your wine though.
Yep. This is probably carried over from OOO's other game, YPP (Puzzle Pirates). Their OMs (Ocean Masters) all have Greek god/titan themed names (mainly the ones you listed, plus a few more). I think it was a type of theme that kinda just stuck, but I don't really know the origin of it.

Hermes
Boswick
Quicksilver
Pinwheel
(not GM's but I needed someway to bring up Hermes...)
"If I was a Greek GM, I would be Dionysus.
It's obvious why, isn't it?"
Unfortunately, it's already taken by a Y!PP OM ("GM").

Pff, he's not half the alcoholic man-child with bearded goat men followers I am.

Coriolis and Equinox are Agents in Whirled and they get their names from natural phenomena.
Just to fill the void :) All of the current GMs are either OMs on YPP or Agents in Whirled. And then they carried their names here.
The more you know!
Yup, every GM name has a Greek mythology root. I noticed a while back... mostly because I used to play way too much Age of Mythology.