If you need quick ideas for random NPCs and encounters, just open to the relevant page of a Where’s Waldo book and throw some d6s at it. Make the die result how favorable the encounter is to you. Martin Handford’s done all your work for you.
For example: Town Encounters
And so on and so on. Almost every page of those books are useful for ideas. Even anachronistic ones can be easily re-themed into some thing suitable.
And for more random tables than you can shake a goblin’s dismembered leg at, download Maze Rats and never run out of ideas again.
I just found the Paper Towns subreddit, which I’m convinced is one of the best RPG resources I’ve ever seen. It contains hundreds of high-quality paintings and drawings of ancient and medieval cities – just print them out and write a key over them or a random table, and you’ve got yourself multiple sessions of content. Players think completely differently when they can actually see the layout of their surroundings and can plan accordingly. Here’s a few of my favorite maps below.
Great little port town. The details in the whole harbor/fort complex look especially interesting.
The elevation in this one is great, as are all the ways around the rooftops and the twisting roads.
Diocletian’s palace is basically begging to get robbed by some murderhoboes in the dead of night.
I love how concrete and specific this one is. You get encounter hook ideas just looking closely at it.