PassyHi Passy,
I reached out the vendor to answer your question. They stated that there is a possibility of duplicate colors since there are different styles of threads but they do their best to limit them.
I participated in this drop a few months ago, and I got six colors that were duplicated exactly and another four that were very close to having duplicates. In general though, these ten colors are useful colors for me. I also didn’t get any of the Highlights (neon) colors, which I was a little disappointed about. But the thread is great and I’m glad I bought this set!