Writing

Ink is forbidden.
Because the written word is viewed as sacred and unchangeable, far beyond the understanding or control of the average person
Contracts, therefore, are signed only by magic or blood.

(catch me establishing contract law right out the gate...and oooooh, lawyer clerics has potential...)

Numbers are considered to be the closest one can get to the writing of the god(s).

Being bad at math is close to herecy
this is the general feeling amongst the more 'wizardy' sides of the clergy

Dreams can be viewed by others as they happen.

Items can be used to earn magical abilities.
Magical ability can also be affected by location (ie edge of a volcano, local coffee shop, house you grew up in, etc.).

A non-zero number of folklore/mythological beings exist. Which ones, how many, and if they fit the stories? ¯\\_(ツ)\_/¯
(hundreds)
(one of them is Mothman, probably)
(the rest? magnificent body horror creatures and cute things like griffons and chimeras. not the FullMetal Alchemist kind.)
is there just one Mothman? or is it like mailman or tall man, where there are manyDragons exist.we're gonna have to decide, like, sentience level, for all magic creatures. does an owlbear work at a bakery? do dragons skip out on their taxes? have heffalumps taken over the local mafia?
i kind of enjoy more bestial dragons but, like, HTTYD type of bestial
kitty!dragons
can be completely wild, can possibly be domesticated, that sort of thing
although, i do enjoy conversational dragons a la patricia wrede
some can be conversational, some are bestial, then?
there could even be draconic humanoids, similar to how there are humans and monkeys

dragons exist and they emit contagious emotions that means everyone around them feels what they feel
people who are able to have particularly erotic, vivid or lucid dreams hire themselves out as a picture show. there is a roaring trade in psychoactive dream-altering drugs. people who don't want to disclose embarrassing secrets enchant themselves so that they don't dream at all, and they don't sleep as well as a result.(edited)
graffiti becomes a powerful act of political resistance against the sanctity of the written word. underground rebel preachers teach people to read and write to democratise the written word.
an original idea/jumping-off point: some tattoos are heritable.another one: a large number of people in the history of a city/place chose to be petrified.
people that chose to be petrified had a number of reasons for doing so, one of which being that the rich pay a fine amount of money to have as realistic statues around as possible. if you were poor yet attractive, you could become petrified and give the money to your family. another reason is simple vanity or a desire to be remembered exactly as they were. historical figures, such as generals or inventors or even artists them selves in particular, didn't want anyone misrepresenting them.
Anyone can rewrite public history if they pay historians enough money.
As a consequence, people develop a rich oral historical tradition which becomes more trusted than official sources. Storytellers and skalds and bards are commonplace.(edited)
I think maybe some people might be petrified kind of like cryogenic storage/to await a certain future event or time and get "woken up"
that would be a fun character hook. playing someone from the far past who has just been woken up and is like....what the hell are kids wearing these days!
oh and I missed "Gravity can be controlled": the local version of the stocks is to suspend criminals up in the air by affecting gravity so people can throw rotten vegetables at them that way. people who fear assassination by being thrown into the air by the weakening of gravity wear heavy boots or carry parachutes.
magical creatures who exist ideas: ghosts, but they can't perceive the living
seabirds are the souls of dead sailorsBoth guns and swords/axes/etc. are used.