The gods and powers of the Flanaess are an often-confusing mix of deities from a handful of cultures, representing natural powers and human attributes, virtues (and vices), and mental and emotional states.
In such an environment, the powers and attributes of some gods overlap. Certain others, generally demigods or hero-gods, are once-mortal heroes (or villains) who have attained godlike powers.
Most humans and demihumans worship one or two primary gods, but their worship is by no means exclusionist. The people of the Flanaess are pragmatists, and they willingly embrace as many gods as necessary to make their lives run more smoothly. While a farmer may worship the old Flan goddess Beory as the Oerth Mother, he may also offer money or tribute to the Suel god Phyton to bring fertility to his fields. More than this, whenever the farmer strays into nonagricultural endeavors, he may very well offer tribute to the god or gods appropriate to whatever he is doing. For instance, if he travels to the City of Greyhawk to sell his products in the market there, he may at different times during his trip offer tribute to Fharlanghn (god of travel), St. Cuthbert (god of wisdom), Velnius (god of weather) and Zilchus (god of money). A lot of this "worship" will look perfunctory, like tossing coins into a fountain for luck, but it will be no less genuine for that. The people of the Flanaess feel their gods are real and can take concrete action on the material plane. This feeling isn't changed by the fact that the most powerful gods rarely involve themselves directly with happenings on Oerth, St. Cuthbert being an occasional exception to this.
In the Greyhawk setting, gods are able to grant spells to their clerics at the following levels (assuming the cleric's Wisdom score allows):
Greater Deities. Clerics can access 7th-level spells.
Lesser Deities. Clerics can access up to 6th-level spells unless deity resides on Oerth (example: Fharlanghn's priests can get up to 7th-level spells, as he wanders Oerth).
Demi-Gods. Clerics can access up to 5th-level spells unless the deity lives on Oerth, in which case 6th-level spells can be acquired (examples: Iuz and Wastri)
Hero-deities. Clerics can access up to 4th-level spells unless the deity lives on Oerth, in which case 5th-level spells can be acquired.
Fiends. These are Powers of the Lower Planes (Arch-devils, Demon Lords/Queens, etc.). Clerical spells are granted via special rituals. Spell list is limited and spell level access can be limited based on type of sacrifice.
Heroes (Quasi-Deities). These personages do not grant spells.
Imprisoned gods. Tharizdun, Vatun, and Vecna are imprisoned. Their priests can access up to 2nd-level spells only.
Regardless of deity classification, druids can access spells of any level up to the limit specified by their Wisdom score.
Name. Deity's accepted proper name.
Origin. The ethnic group/human race with which the deity is usually associated. Common: Commonly accepted across the Flanaess in many regions and cultures, and actual origin is irrelevant. Deities that are not commonly accepted are worshipped primarily in areas settled by the listed ethnic group (for example, Osprem's shrines and temples are likely found only in areas where the Suloise have settled: in this case, along seacoasts). Some deities have very limited worship, though their names might be widely known; this is particularly true of extremely Evil gods such as Tharizdun.
Portfolios. The deity's best known spheres of interest are given here, with a few attributes usually associated with that deity.
Alignment. This is the deity's primary alignment. Worshipers alignment are indicated in parenthesis. A priest can be any matching alignment, but certain tests call for an exact match with the primary alignment (typically experienced at very high levels).
Worshipers. This shows the occupations of the worshipers of a deity. Unless otherwise stated, most of the worshipers of each deity are assumed to be human.
Name
Beory
Boccob
Corellon Larethian
Garl Glittergold
Gruumsh
Incabulos
Istus
Kord
Lendor
Maglubiyet
Moradin
Nerull
Pelor
Procan
Rao
Tharizdun
Ulaa
Wee Jas
Yondalla
Zilchus
Portfolio
Oerth Mother, Nature, Rain
Magic, Arcane Knowledge, Balance
Elves, Magic, Arts, Music, War
Gnomes, Luck, Trickery
Orcs, War, Hatred, Victory
Plagues, Famine, Nightmares, Disasters
Fate, Destiny, Divination, Future
Athletics, Brawling, Strength, Courage
Time, Tedium, Patience, Study
Goblins, War, Depths, Darkness
Dwarves, Artifice, Family, Loyalty
Death, Darkness, Murder, Underworld
Sun, Light, Strength, Healing
Seas, Sea Life, Salt, Sea Wealth, Navigation
Peace, Reason, Serenity
Eternal Darkness, Entropy, Insanity
Hills, Mountains, Gemstones
Magic, Death, Vanity, Law
Halflings, Protection, Fertility
Power, Money, Business, Influence
Align
N-NG
N
CG
LG
LE
NE
N
CG
LN
LE
LG
NE
NG
CN
LG
NE
LG
LN-LE
LG
LN
Worshipers
Any/druids (no clerics), farmers, rustic Flan tribes
Any/wizards, sages, seers, diviners
Any Good/elves
LG/gnomes
Any Evil/orcs
Any Evil/intriguers, rebels, destroyers
Any/most Baklunish folk, seers
CG, CN, NG, N/barbarians, athletes, warriors
LN/sages, timekeepers, astronomers, wizards
Any Evil/ goblinoids
LG/dwarves
Any Evil/assassins, thieves, necromancers, humanoids
Any non-Evil
Any non-Lawful/sailors, fishers
LG, NG, LN/paladins, peacemakers, wizards
Any Evil/the insane, psychopaths, destroyers
LG, NG, LN, N/dwarves, gnomes, miners-hill dwellers
LE, NE, LN, N/wizards, lawful necromancers
LG/halflings
LN, LG, N, NG/merchants, guildsfolk, accountants