That's tough. Perhaps if you clarified exactly what you need and what you need it for. There are thousands of cities in the world and all are a bit different and the type you need is probably relative to where your clients are located. You can try to search Google images for things like "Urban Communities", "Urban Centers", "Town Square", etc. I still say your best bet is to get out with a camera and spend a day in an area relevant to your archvis projects and take as many photos as you can. If you want 3D backgrounds that are ready made with all that stuff in it, I know of nothing like that on the market, except for hobbyist software like DAZ3D and iClone. Most archvis professionals want more control over their projects and would rather create the entourage and backgrounds themselves so it doesn't look like they just drop clip art into their scene.
