I have a couple of people who I cannot find a burial site for.
Michael Lutz, protestant probably Lutheran or Methodist, died sometime between 1885-1890.
Anna Woelfel, born 1827, and died after 1891, as they seem to make reference to her, as survivor, on her husband's death cert. but she is not buried where her husband is. She was probably Catholic. I'm pretty sure she didn't make it to the 1900 census.
Besides calling or initiating a search with every cemetery in the greater NYC are, I don't know how to track this down.