Weekly ApparelX gives a thorough explanation of "button manufacturers."
Buttons are such an important trim that it is no exaggeration to say that whoever controls buttons controls design! This time, we will introduce three button manufacturers available on ApparelX.
IRIS page → https://www.apparelx.jp/search.php?maker=201
Daipla page → https://www.apparelx.jp/search.php?maker=207
Sakamoto Saji Shoten page → https://www.apparelx.jp/search.php?maker=208