There used to be a big sign on the Coney Island Boardwalk for Hygrade brand hot dogs, which sound very 1960s school lunch-ish (and not particularly appetizing). This sign, in remarkably good condition, is on Sixth Avenue and Bleecker Street in a little park called Sir Winston Churchill Square.
Uneeda Biscuits were actually crackers introduced in 1898 by the new Nabisco company. Other Uneeda Biscuit ads survive on city buildings; this one can be found in downtown Brooklyn near the Manhattan Bridge.