Divine boons are the supernatural powers given to faithful followers by their gods. It doesn't matter what class they are, nor level. As long as they are faithful and follow the tennents of their religion, the people (or monsters) gain the boon. These are not balanced against each other and are not feats. They are meant to be rewards for roleplaying in all editions. Characters who do not have faith get squat. I used many of the spheres from 2e and domains from 3e (PH and Spell Compendium) as the basis of the boons rather than actual gods. This is meant to allow you an easier time adapting boons to your settings. I suggest a single boon no matter how many portfolios or domains a god has but you can increase that for high level characters if you want.
2e
Animal- small animals are friendly to the character. They will not attack unless magically compelled.
Chaos- art created by the character is worth three times as much. Plants grown by the character have unique shapes and may or may not be worth more.
Charm- the character always looks dapper (even if they swim through mud). They can also command children and have their orders obeyed most of the time.
Creation- the character can make a single tool from thin air. It must be no heavier than two pounds. If another tool is created, the former one ceases to exist.
Divination- the character will know visitors to their home or campsite. They can not be suprised and know the visitor's name.
Guardian- the character can provide a 1 point bonus to armor class and +2 to saving throws to one other character or creature within a few feet. This lasts as long as the target lives.
Healing- the healing rate of the character is doubled.
Law- the faithful detects crime. It requires the crime to be committed near the character.
Necromantic- the character sees death. Anything with a life force that dies within line of sight will be apparent to the character.
Numbers- with effort, the character can create minor extradimensional spaces. Worshipper homes and temples will be larger on the inside.
Plant- diseased and infested plants are cured with a week's worth of effort. The plants will not die in that time even if they normally would and recover completely.
Protection- the character has a one point bonus to armor class or +2 to a saving throw.
Summoning- the faithful can call a small object to hand. It has to be within line of sight and weight no more than five pounds.
Sun- the character can never be blinded. Even removal of eyes will not stop them from seeing normally.
Thought- the faithful can sense strong emotions in others.
Time- the duration of a process is known ahead of its completion. This may be a mundane task or a magical one, though it does not apply to magical research as there are too many variables in such.
Travelers- the faithful has two powers. If in a rush, overland movement is doubled. If ambling, the character will find things to assist in survival.
War- the character can study the terrain and gain an extra bonus (attack roll, armor class, saving throw) while in said location.
Wards- the faithful can see gaps in their defenses even if there is magic hiding such.
Weather- the faithful can sense the weather no matter how deep underground they are. This also allows them to know how deep they are.
3e PH
Destruction- the faithful can destroy weak objects from a short distance. This can not harm metal, stone or other hard objects without a very long time to work on them.
Evil- the character has a falseface and can lie to others without being detected.
Good- the faithful can forgive the sins of others, thus giving them a chance to change their alignments to good without penalty.
Knowledge- mundane books and scrolls automatically correct any false information if placed within the faithful's library. This takes weeks to months depending on the work's length.
Luck- the faithful finds wealth. It may be a fallen coin or a letter of introduction to a bank. They are never without some money.
Magic- the faithful senses the weave of magic. Ambient magic, the results of casting in the past as well as ley lines and the such, can be detected and analyzed.
Trickery- the character can hide a small object on their person and it can not be detected by others, even those looking upon it.
Spell Compendium
Balance- the faithful senses extremes of alignment. This usually does not work on mortals unless they are extreme in their beliefs.
Community- the faithful can welcome people to their community, providing an encounter bonus thereafter.
Dragon- the faithful can infuse dragonic energy into the food they prepare. Those who eat this food take much longer to tire.
Dream- the character and those around them are immune to mundane nightmares.
Family- the character can automatically create a child with a willing partner.
Moon- the faithful can call the tides, allowing a ship (or large creature) to escape a shallow area.
Ocean- the faithful can drink seawater and eat kelp without harm.
Planning- any mundane process that was planned has its time reduced by one quarter.
Purification- the faithful can not spread disease even if they are ill.
Renewal- objects can be recycled as long as they are turned into something with a different function.
Trade- the faithful can sense the value of objects, find the hidden gems so to speak.
Wealth- the character can breed coins. The more coins there are intially, the more will appear in time. Every few months the pile doubles in size.
Of course a god may have several boons to give and the DM should be the one to decide which a player character gains. This may change with the acts of the character. Pleas and sacrifices are useful in this regard.