After finishing OG 10 through 13 and the other official resources, I was looking for more official GMAT questions and came across the
GMAT Paper Tests. I found the
GMAT Quantum list of unique questions in these tests.
Later, a friend who took GMAT long time ago and owned both paper tests and the OG 10 told me that the first test of each set were reproduced in OG 10. Moreover, all the RCs were reproduced in OG 10. This matches with the quant list from GMAT Quantum. With the help of my friend, I prepared a list of unique questions attached with this post.
Each set will give two unique and one repeated tests. Each of the unique ones contains 32 PS, 20 DS, 22 SC, 16 CR and 0 RC questions. A total of 90 unique questions per test. About 180 questions per set. Each set sells for $30, that is 16.67 cents per question or 6 questions per dollar. If you compare with the 158 new questions from OG 13, you can get a question for 9.3 cents or 6.58 questions per dollar. So I don't see a reason to spend $90 to buy very very old test question that may not be useful anymore.
I decided to post this bit of research for someone who might one day consider buying or actually buy these tests and search for unique questions.