From the Introduction:
Phonomicon ex Cultis is an aid for any, primarily fantasy, roleplaying game; a glorified random table of cults for your PCs or NPCs to follow.
This work came about initially as a supplement to a megadungeon project I am/was working on to help add flavour to the randomly generated dungeon inhabitants by providing generic cults, religions and traditions the NPCs might respect. It developed and took on extra life in part inspired by the Petty Gods project led by James Maliszewski over at grognardia.blogspot.com. Kudos to one of the OSR heavyweights!
The premise behind Phonomicon ex Cultis is simple. At its heart, it's a table of 100 gods, goddesses and powers to provide a pan-system source of small religions as a springboard for use in your roleplaying game. The concept underpinning this was to take the most common phonemes (or word sounds) in the English language and use them as a basis for generating powers that NPCs worship. If words have power, then do sounds have power too? And if similar sounding words can be grouped by similar meaning, do they take on further strength?
Take AIN as an example - you'll find it in slain, sprain, strain, pain... all words concerning damage and discomfort - and all of a sudden you have AIN, Patron Deity of Injuries. Perhaps the civilised folk known him as Bain, and appeal to him for a quick recovery from wounds; perhaps the barbaric humanoid tribes know him as Tarrainain, and revel in his name as they butcher villages in their path; further still, perhaps the snake-headed Inquisitors of Koth whisper their prayers to Ain'ts'sain as they prepare the torture implements for the next victim.
System Agnostic
This book was designed to be system- and setting-agnostic - that is to say, information is presented in such a way to be readily adapted to use in any campaign, regardless of whether it's any edition of D&D, Palladium, Runequest, or set in Blackmoor, Tékumel, or Glorantha.
Any mechanic described in this book will be described as a 'bonus' or 'penalty', or a level-dependant amount/adjusted, 'LDA'. The value of each effect is left to the discretion of the GM - in a d20 based system, a bonus may be +1 or +2, whereas in a percentile system, it may be +5% or +10%. Powers may typically be usable 1 or 3 times per day, depending on its strength in a given system. LDA damage or power may involve rolling a d4 for each level of the cultist in D&D, or d6 in Palladium. How these effects are resisted, or if indeed they can be resisted, is up to you. You, GM, are the judge, and you know what works in your system - and if it proves it doesn't, change it.
Using this book
This book is designed to be referenced in two kinds of situations
A GM designing a dungeon/quest who wants some ideas for potential cults to which the NPC inhabitants might belong
A GM or player faced with coming up with a new (or alternative name for an existing) obscure religion/cult on the fly
What follows is a list of 100 possible patrons for your cult, along with some optional fluff or detail, which can be used as much or as little as you want. It's designed more to be a springboard for ideas and improvisation than anything concrete - pick anything from the entry to use. So, once you are ready, roll a d100 and select from the relevant table below.