Along the large chains mentioned above, there are countless independent stores specialised in handycraft. Sakura Horikiri, situated in Asakusbashi, is a fine example.
There you will not only find materials, but workshops are regularly organized too.
https://www.sakurahorikiri.co.jp/
For those interested, Asakubashi has many stores dedicated to jewellery making, while Nippori is known as “fabric town”, where you will be able to find unique patterns, much cheaper than in central Tokyo.
Poras Raoul Jean Raymond ポラス ラウル ジーンレイモンド