I will search up to 8 different years of Buffalo City Directories for a particular name or (in later directories) address, and provide scans of the corresponding pages.
City directories have been published since 1828, with occasional gaps. The directories include only residents of the City of Buffalo itself.
Listings for individuals are sorted by name, and typically give their occupation and address, and often a spouse’s first name. In 1929 and later, a second section of the directory is sorted by street address, and gives the name of the head of household. (If you know the year a person died, looking up who owned their house the following year may sometimes prove useful.)
Note that many earlier Buffalo directories are available for free online – see buffaloresearch.com for a list. Ancestry.com also has some of the directories between 1875 and 1956 in their U. S. City Directories collection.