FamilySearch.org and GermanGenealogy.org (or ItalianGen but I don't like their search) are among the most useful sites, although Ancestry is catching up. None are complete, and be aware of transcription errors where names are not indexed exactly right.
Records are public up until 1949. You can order copies online from the Department of Records (aka DORIS) if you have enough information.
See https://www1.nyc.gov/site/records/historical-records/genealogy.page for more complete information including where to search.
Researching Goldner, Singer, Neuman, Braun, Schwartz, Reichfeld (Hungary/Slovakia); Adler, Roth, Ader (Galicia); Soltz/Shultz (Vitebsk, maybe Lithuania)