Here is a beautifully-drawn collection of maps which ought to spawn a few ideas even if they do not suit adventures you already have to hand.
The range is tremendous. To start with, do you want a grid or not? Next many of the maps come in both day and night versions - the night ones show, when buildings are present, where light would shine out of the windows (useful information if someone is attempting to sneak up unobserved).
Formal gardens for noble villas, a whole township, an adventurers' camp somewhere in the wilds, a vertiginous balcony with a cityscape far below, a dock, a swamp, city blocks... no matter where your adventures take you, there's a good chance that there will be something of use here. A couple of inns to rest your weary bones... and a gaol for those adventurers who misbehave themselves. Oh, and a town hall should they choose to indulge in politics, and sewers...
A really nice collection to have to hand, ready for when they are needed.