Hi! Thank you so much for leaving a comment here, it really helps me a lot!
Regarding your question, to be completely honest with you, even if I had a very large catalog of cities like this one and my previous ones, I don't think it would be worth doing something like that. It would probably be better to look for a specific asset pack that already includes what you need, just to save yourself some time.
That being said, your message actually gave me the idea to make something like what you're asking for. When I have some free time, probably next week after I finish another city, I might make something along those lines. Or feel free to message me privately and I can make something more specific for you.
Although modifying an existing pack isn't a bad idea either, that's honestly what I'd recommend so you can save yourself some time.
Good luck with your projects!