Here is the list of my favorite website where I do research.
City History and Architecture of NYC
NYCgo NYC & Company is the official destination marketing organization for the five boroughs of New York City.
Untapped Cities Rediscover your city. Untapped Cities unearths New York City’s most unique and surprising places, stories and events for the inquisitive reader. We are a community of over 600 passionate contributors, interested in what’s hidden and unnoticed, and how our history informs city life now and in the future.
Brooklyn Historical Society: Founded in 1863, Brooklyn Historical Society is a nationally recognized urban history center dedicated to preserving and encouraging the study of Brooklyn’s extraordinary 400-year history.
Architober: NYC’s architecture and design month features hundreds of events, tours, and exhibitions organized by more than 60 partners across the five boroughs.