I've always really liked the rice method when I'm drawing a map and feeling a little uncreative. I'm not sure if this would help much with actual city layouts, but it could help you get a general idea for a shape! Plus it's kind of fun to dink around with haha.
There's also a program called AutoRealm, I've never really messed around with but I think it has city mapping capabilities as well as other general mappy stuff. My friend used it to make a map for his DnD campaign recently and he really loved it.
