Steal from your local news.
Police, detective, crime dramas and most other shows are full of plots for a city game.

Cities are rife with adventure potential oof every sort.
My advice, set up some dynamic Factions and NPC hooks first and then let your PCs set out wirh their own goals
Steal from your local news.Police, detective, crime dramas and most other shows are full of plots for a city game.
Also look at crazy history stories, examples: Shanghaied, press gangs, Edinburgh body snatchers, London undergrounds and such. The biggest thing in a city is figuring if something mundane or supernatural.I'm running a sandboxy campaign - it's my preference. The intro sessions involved rubbing against a crime boss who had hired folks to poison the (very pricey) booze consumed by a Baron. The crime boss is way too powerful for them, but if they go hunting....
[rubs hands together]
I spent 20 years in journalism, mostly at the "community news" level. That's a good inspiration for the sandboxy stuff. Houses burning; drunks being arrested. Occasionally a brawl. In a world with magic ....
I'm running a campaign in a bustling city, somewhat of a composite of Monte Cook's Ptolus and Freeport. Can you recommend some published city adventures? How about your own adventure seeds?
I'm looking for the city to be the adventure setting, as opposed to trecking out to some nearby dungeon or fortress.
Thanks!
Something I do with my players is allow them a number of NPCs that they can pull out at any given time. Say a player needs a to see a friend he knows of, so he just gives a description and brief backstory and I as the GM create the location where he can find them. Only rules I have most be a reasonable connection for the player to know them.Do you have a small set of procedures for down time activities, that characters may pursue on their own?
Do you have a list of major personalities (NPCs) whom you might integrate into stuff like carousing, or other kind of curated encounter table, so that PCs can meet them (and the organizations they may be a part of), on multiple occasions?
Do you have a means to track proactive decisions made by the party, or factions in the city, as well as what their responses might be to actions done to them (such as clocks, or the like)?
I mention these because they are all ways of devising adventure seeds, that may not necessarily be tied to a major story beat you might find in a published city adventure or module.