Fabric. Rolls and rolls of fabric.
The street is well marked in English. In fact, there are way finding signs from the nearest subway station (the Nippori Station of the JR Yaminote line). Be prepared to take stairs down from the subway station. After that, the roadway is flat. Some stores have stairs; some have stairs and elevators.
The store where I got closest to buying something.
The cutest panels for the most darling items.
There were stores for fancies, stores for wool, stores for buttons and trim. It was fascinating and overwhelming.