3. The Pantheon of Greyhawk
Before getting into the actual pantheon, a reminder- Gygax was always human-centric. So the deities in Greyhawk were traditionally deities for humans. Non-humans had slim pickings. That's something I assume people will want to change. In addition, Gygax divided the deities into four groups- those that were widely worshipped by all, and those that were primarily worshipped by one of the main human heritages (Baklunish, Oerdian, Suel, and Flan). That is why there is occasionally some overlap between the gods. Finally, there are three gods that are just, um, there (Ulaa, Wastri, and Thari... SHUT YER PIE HOLE!).
So, what is the "Greyhawk Pantheon" (as of 1983)? This doesn't include the "non-human" deities. Sorry, Raxivort.
Allitur (ethics, Good)
Atroa (spring, Good)
Beltar (malice, Evil)
Beory (Oerth Mother, Good)
Berei (family, Good)
Blerred (mines, Neutral)
Boccob (magic, Neutral)
Bralm (industriousness, Good)
Celestian (stars, Neutral)
Delleb (reason, Good)
Ehlonna (forests, Good)
Erythnul (slaughter, Evil)
Fharlanghn (travel, Neutral)
Fortubo (stone, Good)
Geshtai (rivers, Good)
Heironeous (chivalry, Good)
Hextor (war, Evil)
Incabulos (plague, Evil)
Istus (fate, Neutral)
Iuz (oppression, Evil)
Joramy (volcanoes, Good)
Kord (athletics, Good)
Kurell (jealousy, Neutral)
Lendor (time, Neutral)
Lirr (poetry, Good)
Llerg (beasts, Neutral)
Myhriss (love, Good)
Nerull (death, Evil)
Norebo (luck, Neutral)
Obad-hai (nature, Neutral)
Olidammara (music, Neutral)
Pelor (sun, Good)
Phaulkon (air, Good)
Phyton (beauty, Good)
Pholtus (resolution, Good)
Procan (oceans, Good)
Pyremius (murder, Evil)
Ralishaz (madness, Evil)
Rao (peace, Good)
Rudd (luck, Neutral)
St. Cuthbert (forthrightness, Good)
Syrul (deceit, Evil)
NOT GONNA WRITE IT (eternal darkness, Evil)
Trithereon (liberty, Good)
Ulaa (hills, Good)
Wastri (bigotry, Evil)
Xan Yae (shadows, Neutral)
Zagyg (humor, Good)
Zuoken (physical & mental mastery, Neutral)
If you add in quasi-deities, you can see ... that's a lot! Now, I will admit, not all the names are equally ... compelling today. St. Cuthbert, I'm looking at you. But it's a fascinating list. The other important thing to recognize is that Greyhawk (and Gygax) embraced an idea of "muscular neutrality," which meant that, for example, not all "good" deities were the same type of good. Pholtus, for example, was known for rigidity. Zagyg, of course, was a mortal who became so powerful he rose to godhood. And Iuz ... well, he's a god and he's busy meddling in the affairs of Greyhawk.
The basic point of all of this is that the pantheon of Greyhawk is .... LARGE ... and that the nature of divinity in Greyhawk is traditionally more porous than what we are used to seeing. But with all that in mind, feel free to use whatever works best for your Greyhawk!