religions in my campaigns

Armchair is employed again. Not sure this mean I will be posting any more frequently. But here we are.

I am working as a teller at a bank. One of my first realizations about this work was how extremely religion-esque it all is.
A bank is like a temple of ancient Egypt or Mesopotamia. There are rites which must be observed for the glory of our god. There are public rites like those performed at the drive-thru teller window, where supplicants come to make offerings and petitions to their god. And there are private, inner rites where we balance the cash in the vault. I and my fellow employees are the priesthood of this temple.
And it goes without saying, but money is our god.
In other city-states, they worship Yuan or Euro or Rupee. But we call our god Dollar.

In a common manner of speaking, religion is a matter of faith. Anybody with a basic understanding of economics knows that money is not intrinsically valuable. It is only of value because people agree to believe that it is. It is a matter of faith.
When a person questions their faith, it weakens their religion. When a teenager actually questions whether they really believe in the god their parents take them to church to worship, it weakens the religion as a mass belief system.
So an ideal religion is one in which the believer never thinks to question their belief and never compromises their faith. And if they do, they should have no option but to carry on practicing their faith as if they believed it wholeheartedly. When I consider our relationship to money, It seems that money is just such a faith.

As to D&D;
I've mostly played 3rd edition. It annoys me immensely that the 3E books have a listing of gods which it strongly suggests the character worship. The gods are all from the Forgotten Realms setting: the vanilla D&D setting. This annoys me to no ends. It conflates system and setting, as if deity were as fundamental to a character as their class or ability scores.
So I discourage the use of the gods in the book. In my games, I present a pantheon which I consider to be vastly more interesting.
 
Old Boy
The Old Boy was a sage of ancient times who, according to legend, was born with a long, white beard and uncanny wisdom. His philosophy hinges on the idea that a person is either in harmony with the way of the universe, or not. To be in harmony is to enjoy ease and joy, and if you are not, it means you are making trouble for yourself and others without good reason.

The writing of Old Boy maintain simplicity as a virtue, value self control, compassion and understanding. The spiritual legacy of Old Boy is broad indeed. His reverants range from simple farmers, to bureaucrats, to monasteries of cloistered monks, mountaintop ascetics, or wandering guardians of justice.

Morgi
The cults of Morgi are secretive and reclusive. She is not a goddess for the masses. Morgi is the name given to the utter glistening blackness of being which lies before the beginning, and after the end. She represents both nothingness and utmost potential.

When personified as an idol, Morgi is depicted as a dark-haired woman with a dark, star-studded cape. Her worshippers congregate in private, exclusive cults. The revel in the Morgi, believing her to be the ultimate aspect of reality. While they are not exactly a charitable organization, they believe in maintaining the spectrum of potential which arises from their mistress, and may help endangered entities, ideologies or species.

Cthona
Is a personification of the planet and natural world. Followers of Cthona believe that the natural world has an intelligence of its own, and they believe that it is possible to commune with it. Cthona is usually referred to in the feminine. Followers of the Cthonic religion treat their religion as a practical matter rather than an abstract or intellectual pursuit. Their morality extends beyond human relations, and takes the concerns of other species or ecological inter-dependencies into account. Because of this, they can seem amoral or irreligious to followers of other faiths. Some Cthonics are very cynical of other religions, saying "We worship nature, for there is no doubt that she is real."

Hyponica
A psychopomp Goddess, who guards the souls of mortals in this world and the next. Her priesthood is well versed in what passes for psychological science or spiritual alchemy. They practice divination, dream interpretation and offer counseling to supplicants. They are seriously concerned with the sanctity of funereal rites, and the safe transmission of the soul from this life into the next. Their priesthood has a particular hatred of the undead. The followers of Hyponica believe that their Goddess was once a mortal woman, whose spiritual power enabled her to become a deity upon her own death. Hyponica is depicted as a woman pouring liquid from one cup into another.

The Pet Rock Faith
Originally practiced among dwarves and gnomes, The Pet Rock faith has a broad scattering of adherents of many walks of life. Adherents pray to a small stone or jewel which they keep with them at all times, usually in a pouch around the neck or tied around the waist. Followers of more formal religions scoff at the Pet Rock faith as being simplistic and superstitious. But nonetheless, Rockers have been known to perform acts of miraculous healing and magical protection with no other explanation than the power of their faith. 

Protective Avatar
A good deity believed to take mortal form in order to defend the weak and defeat evil. Protective Avatar is believed to have many incarnations in many times. Sometimes, these avatars are said to be unaware of their divine nature. Other manifestations are more plainly miraculous. Protective Avatar is worshipped by good warriors who wish to emulate legendary heroism, or prayed to by common people in  times of need. The religion of Protective Avatar is very simple in terms of its teachings, so its few clerics tend to be men of action. The religion of PA is often criticized for claiming as Avatars  heroes who were either champions of other religions or entirely secular.    

Heavenly Patriarch
The followers of Heavenly Patriarch claim that their god is the Ultimate God of everything, and creator of the whole universe. They have the  habit of capitalizing the word "god" when referring to Heavenly Patriarch, but refusing to capitalize it when referring to the gods of other religions. Heavenly Patriarch is said to be omnipotent, to define the ultimate standard of morality, and is often depicted as a human. Clerics of HP are often at a loss to explain the existence of other deities, demons, or the provenance of evil and usually offer faith-based arguments in explanation. Critics of HP are quick to point out that he may not be the creator of everything, but is probably a more conventional sort of deity. This quickly earns the ire of HP and his clerics.

This list is hardly exhaustive. In the gonzo D&D settings I like, it's fair to assume that every race, city-state or competing ideology has its own religion. In a game where wizards can gain god-like power, reality is frequently invaded by demon-lords, and the nature of the multiverse is only hazily defined, Divinity and what it means are really up for grabs.