Deities. Ready? Let's begin:
Allitur. Wow, so here's a deity I know nearly zero about that is quite cool in reality. Lawful Good deity of ethics, brother of Rao and ally of Heironeous. Allitur is a liaison to other pantheons. Meaning? He can go to Faerun and talk to Mystra or Bane. What other D&D god does that? Allitur's domain, Emyprea is cool too (nod to Frank Mantzer). It's numerous healing fountains and hospitals makes this place a great destination for heroes on a planar quest.
Beory. Good old Mother Oerth, a flan deity like Allitur, she is above the concerns of lesser deities. Beory is a druidic type goddess who is the embodiment of the planet. This of course makes me wonder if the magical alloy Oerthblood, is then literally the divine blood (or essence) of Beory. And does mortals mining it, anger her?
Celestian. If Beory embodies the planet, does Celestian the god of stars and space embody everything else in Greyspace? I doubt it. His basic description is inspiring travel by navigating the stars and understanding their patterns. He isn't a greater god after all, he is more like his brother Fharlanghn and is a guide of travelers. Celestian in fact hangs out with quasi-deities like Murlynd, Heward and Keoghtom. not Beory or Allitur.
Daern. Hero-deity of fortifications. I'm a big fan of Greyhawk's ascended mortals to demigodhood. It echoes real life mythology (Hercules) and it gives players something to aspire to as heroes. What always struck me funny about Daern's addition to the pantheon (around 2E I think?) was that the deity is female. Everyone has heard of the Daern's Instant Fortress magic item from 1E, but who made the choice to say Daern is a woman, when for all those years I assumed (and I know I'm not alone) it was male. I'm glad Daern is female, but in hindsight it seems like a sly move that went under the radar.
Ehlonna. Called Ehlenestra by the elves, she is one of those dual human-demihuman deities that the setting provided in the early days before the elves, orcs, dwarves, etc. got their own pantheons. Ehlonna is the proverbial princess surrounded by unicorns and faeries in a sylvan forest. She is an archer as well, having the famous Quiver of Ehlonna to her name.
Fharlanghn. Speaking of wandering deities, Fharlanghn is the earth-bound brother of Celestian. He knows all there is to know about the geography of the Flanaess, and I imagine, beyond. I've extensively used him in comics to relay lore about Oerth, but never in my games really. Fharlanghn is a fascinating deity, with many relics and allies (and a lover), but be sure to check out his wiki entry, particularly the part about Journey's End. This is another healing destination for heroes much like Empyrea.
Geshtai. I wish this deity of fresh water and wells had more relevance in the setting. She is Baklunish which isn't the primary focus of most DMs, but she comes without any of that real-world religious connotation like Al-Akbar. She's depicted as a young woman carrying a water vessel and has a fish companion named Gummus. How cute, almost Disneyesque.
Heironeous. Everyone knows Heironeous right? Typical good guy war deity with invulnerable skin. One thing that rankles me to this day is how Gygax gave him a magic battle axe as a primary weapon then later editions changed it to a long sword cause boring reasons. At first it does seem odd for your knight-paladin prototype god to have a battle axe, but what got ignored is how it shrinks to 1/20 its size. That's about 3" or keychain size. How many magic swords do that? Further overlooked, Heironeous can throw lightning bolts ala Zeus. What weapon he fights with is moot after that right?
Incabulos. Probably my favorite evil deity since he remains largely underused. Despite this, a lot of what happens in the world at large can be attributed to his portfolio; sickness, famine, drought, nightmares. Incabulos is ever-present even if he isn't actively trying to take over the world. That's why he is a greater deity like Nerull. Death is already a given so his cultists like Incabulos', are just doing his work for him. There is no greater conspiracy involved. Unlike Nerull though, Incabulos' depredations can be countered.
Jascar. Here is a god of hills and mountains that gets little to no attention. The Suel pantheon of Greyhawk, detailed by Len Lakofka in the pages of Dragon Magazine back in the day, really went into depth on these deities, but very few (besides Wee Jas) became what I would call household names among D&D enthusiasts. Jascar is the brother of Fortubo, a smithy god (synergy) and possible cross-over god with dwarves (like mentioned above). Jascar has potential.
Kord. The Brawler. Another important Suel god spun from the same cloth as Jascar and company above, but Kord seemed to achieve a bit of popularity himself in later editions. This is not because of anything in his rich extensive background however. Quiz name his great sword, or his mom and dads name. I highly doubt these things matter to players except that Kord is the typical strong barbarian deity and that explains itself. Check out Kord, he has a lot going on.
Lendor. Let's keep the Suel gods going. Lendor is Kord's grandfather, and to this day I'm not sure if Len Lakofka intended the greater deity Lendor is supposed to be the same as the wizard Lendore who founded the Spindrift Isles/Lendore Isles. He is supposed to be a god of time who has no hand in mortal matters (except choking out occasional chimeras) so maybe not? Someone help me on this.
Mayaheine. Much like Daern, I ceretainly believe Mayaheine was wisely brought in (by Carl Sargent) to give this male-dominated medieval war milieu a female voice during the Greyhawk Wars. Mayaheine is a demigoddess under the service of normally peaceful Pelor. Iuz ust got so out of hand he had to bring in help for Heironeous. I like Mayaheine, there's much left to explore with her background and religion, so I hope she can be elevated to prominence in the future.
Nazarn. This hero-deity is a new addition to the Greyhawk Mythos from 3E era, first appearing in the Living Greyhawk Journal. What makes Nazarn unique is he is a half-orc. I imagine in the evolving structure of this pantheon it was good to have a playable race represented in the lists. Nazarn didn't have it easy, his origin is the arenas of the Scarlet Brotherhood (I would've picked Ull) and he had to impress a half-giant son of Kord with several epic combats before getting Kord's personal approval for godhood. I'd say Nazarn earned his spot.
Olidammara. Good old Olidammara is usually a good go to deity for rogues and bards. He is the Dionysus of Greyhawk as well, so any good tavern in the Flanaess would be well to respect Olid. Over the editions his story has grown to the point we now know he has his own heralds, relics and legends. Read all about it.
Phyton. Oh those wacky Suel gods. So here is another "casualty" of the deity list where for completions sake they have a god devoted to beauty in nature and farming. He is the rival of druids cause he wants to cultivate land, mow lawns and create new types of flowers perhaps. Phyton certainly isn't the 70th choice of an adventuring cleric and that limits his appeal.
Quetzalcoatl. It is not easy finding "Q" deities of course, so the famed winged serpent is probably my last best option. He is of course the head of the Olman pantheon, via the Central American Mythos. Using a literal Earth-origin pantheon made sense before there was a published Oerth pantheon to use, but keeping them is a bad decision that should've been fixed decades after their appearance in Hidden Shrine of Tamoachan. Too late now of course, Quetzalcoatl and company are just another strange twist to the World of Greyhawk's weird side.
Ralishaz. God of bad luck. This is the god a cleric takes if he is chaotic neutral and wants his companions to hate him. Though a male deity, his form switches from male to female often. Either way, he is not good a good god to invoke. This makes it even stranger that he is most popular in Ull, which is a largely agnostic society. I guess Uli really like to curse misfortune on others.
Sotillion. One of the four Oeridian agriculture goddesses, Sotillion is Summer or the south wind. She enjoys comforts of a good life and that is why she is also the wife of Zilchus the god of money. Enough said! Could you imagine playing a cleric of Sotillion? Me neither cause she would never leave the temple for your silly quest.
Trithereon. Now here is a good deity to use. Trithereon is the god of retribution and liberty. He has so much to like, magic weapons, several summonable animal companions and a cool scepter that can banish criminals to a prison demiplane. It's a crying shame in 3E, his retribution portfolio was sponged up by Saint everything is about him Cuthbert. Let Trithereon be his own god!
Urogalan: Okay here is the part of the post where I dig deep into the barrel for a name. Urogalan is the halfling demigod of death. He is not an evil god, more a protector of the dead which seems right for halflings. What I'm curious about is why he is called the Black Hound. What does dogs + death mean in halfling culture?
Velnius. A sky and weather god. Velnius is the eldest brother of the four female wind goddesses and all are children of angry Procan. I love Greyhawk's deity family trees as they include big names and many lesser players. If a god doesn't have family connection they were probably sponsored or served under another god. Sure I grouch a lot about underused D&D gods like Velnius, but in the end his kind are there to provide substance to the overall mythology.
Wenta. Speaking of familial deities, here is one of Sotillion's sisters. The four sisters are collectively called the Velaeri. She is the goddess of Autumn and the West wind. She's probably my favorite because of her association with brewing (Brewfest is abig Greyhawk holiday). Wenta while not a popular deity is one you can often name-drop in taverns in the same breath as Olidammara.
Xerbo. Speaking of ocean god Procan, Xerbo is his main rival as god of the sea. Xerbo is nothing special, a fairly typical Poseidon-lite figure, but Xerbo is also a sailor's deity which would make him (and his wife, sea goddess Osprem) quite popular had Greyhawk been a seafaring focused D&D setting. I know from my own Hold of the Sea Princes campaigns him and the sea gods get more play.
Ye'Cind. Had to dig deep for this one too. Ye'Cind is an elven demigod of music. This patron of bards is most noted for the famous artifact Recorder of Ye'Cind. While Ye'Cind is male (hard to tell with elves) he was named for Gygax's daughter Cindy. I don't think I've ever used Ye'Cind or his Recorder in any of my games. I can't say that about most on this list (except Urogalan).
Zilchus. God of money and business. Amusingly, I based my old comic version of Zilchus on Donald Trump. Well, maybe a more successful, likable version before he went into politics. On the other hand, given the root of his name is "zilch" maybe he has been bankrupt a few times as well.
That's all for now. I don't think there's enough to make a third pass on this A-Z Deity list. Only time will tell. For some other reading on Greyhawk Deities, dash over to Greyhawk Grognard.