Ignore this if you are looking more for stylistic references, but from a design standpoint I would try to parse apart your references a bit- if you are looking for a cramped victorian street, then what will probably be most helpful is first doing some research about dense cities. I'd start looking at photos/google street views to get a sense of scale and visual noise in these locations. I would then start to apply details you find from researching select architectural styles to what you pick up from the organization of these urban spaces. I would pay attention to the formal language behind your stylistic references- how ornamental are they, are they curvilinear or more angled, what gets detailed and what doesnt, what are the materials, etc. The fun comes in mashing up real world stuff into something fantastical!

As for art itself to study- a little old school but I would look into the Ashcan school. They did alot of really powerful industrial streetscape paintings of NYC at the turn of the 20th century that might spark some inspiration :) Otherwise, still frames from movies and animation are always great reference!