My dear friend @dollyjunelondon who is from Tokyo, knows the best places in town really, and she took me to which I think its my favorite stationery store ever, WRAPPLE located inside the PARCO shopping mall in Shibuya.
The address is 15-1 Udagawacho, Shibuya, Tokyo, Japan.
The store is located at the 4th floor of the Parco shopping center, its not too big but they certainly have the most variety amount of masking tape I have seen during my trip.
They have tapes from the brands MT, Aimez les Style, Masté and Yano design between others.