National Hand Tool has fascinated me ever since I was first made aware of the company, and I am grateful to read the information here primarily about the Texas made / finished tools. However, this post centers on wholly Taiwanese tools both imported under the banner of the "National Hand Tool Corporation" name and Taiwanese contract production for Sears, Thorsen Allied Tools, and others.
First, here are two "National Hand Tool Corporation" Taiwanese tool sets I recently purchased, one 1/4" drive and the other 1/2" drive. Note the Dallas zip code which matches that of the the 12827 Valley Branch address. (The 1/2 drive set is missing the original extension and has a Great Neck extension as well as a Great Neck Universal joint that are unrelated to NHT. The two larger sockets are NHT made but did not come with the set originally)

Upon my acquisition of these two sets, I was able to conclusively determine what I have been suspecting - National Hand Tool's Taiwan manufacturing plants were the origination of sockets marked "TAIWAN-RY" (which I assume stands for Ruey Yang), here is a picture of an individual socket from each set.
Based on this information, it can be shown that NHT did contract production for tools sold under the "SEARS" brand as well as Thorsen's import line "Thorsen Allied Tools" as well as an entity which imported tools marked "HTD" (cannot find information about this company, but another GJ member has posted about having an HTD wrench set). Here are examples of the "TAIWAN RY" marking on said tools.

Here are some more pictures of the 1/4 ratchet:

I am also almost certain National Hand Tool or a related company is responsible for tools marked Taiwan Y as well as the Taiwan RY tools.
The spinner from my 1/4 drive is simply marked "Taiwan Y". Here is the spinner as well as a comparison between a "Taiwan Y" and a "Taiwan RY" socket. Many of the components of "SEARS" socket sets available for online purchase are marked with "Taiwan Y" instead of "Taiwan RY" like my "SEARS" socket, but the ratchet looks identical from photos and the case is the same color as the NHT cases. I hope to soon purchase a "SEARS" socket set for ratchet comparison purposes and obtain definitive proof that the "Taiwan Y" sockets are also NHT made.
I have really enjoyed learning about tools here for the past few months on GJ, and I am happy to finally have some information to contribute.