Anything Waterdeep is good, except for Dragon Heist from what Ive heard. Starting with Waterddep and the North for (1E) and City of Splendors (2E & 3E), Volos Guide to Waterdeep (2E). City Systems and Cities of Mystery (2E) have some good tables for randomly generating street scenes. As
@payn said the 3E DMGII is good too, as is Cityscape (3E). Reading through through all the Waterdeep material might take a while but it's worth it. I read it quite extensively and I've been able improvise city games with little to no prep. Just a few things that come to mind that I've used over the years. Is Waterdeep the best city setting, probably not but there is so much to work with that you can modify or disregard as you choose.