RISUS (The Anything RPG) game system.....which I know jack squat about, but it is free, which makes today another bit of a twofer. Toast of the Town is a great 42 page PDF detailing an adventure in the town of Trostig.
Now I only skimmed through the adventure and it felt like there would need to be a fair amount of prep needed to run the thing, but I could easily see tossing the adventure to the side and using Trostig as a cool town in just about any FRPG campaign. There were a lot of cool little details that really made Trostig "pop". Even if, for some reason, you didn't want to run RISUS....didn't want to use Trostig as an in-game locale, I still recommend picking this freebie up for several reasons. First would be those little details you could strip-mine like there's no tomorrow. Lastly would be just to look at the sections of the download to see how the author put things together....I see some great organizational ideas I'd love to steal for my own locale-building.
Toast of the Town is available as a Google Drive download, but I have not added direct links to this post. Instead they go to a holding page on the Cumberland Games & Diversions website which does have those links. I'm not a fan of direct-linking and cutting out the middle-man that made this freebie available in the 1st place.