Source #1 banggood. The blank set on banggood may be of high quality, but has a LED window (shine through as you call it),
who like? me no! :-(

Source #2 taobao. On taobao I couldn’t find blank sets, do you have a link,
ideus?
Source #3 Signature Plastics. The blank DSA sets from Signature Plastics are of lower quality, Signature Plastics itself admits that, quote: “
... it became necessary to reduce costs as much as possible to remain competitive. As a result, subsequent families of keycaps, like the DCS and DSA families, were designed to use less material”.