If you have just one stone with the T shape clearly in relief in your collection, it will be of more value in convincing others that they are man-made than to present a vast collection.
"T" is the age-old symbol of the spirit, as represented by abstract nose and brows on stone. (The connection between stone and spirit continues in gravestones today.) That’s why the eyes are not necessarily carved but implied by the shadows cast. It shows the way to the third eye, the pineal gland. “Spirit” was inscribed in the earliest Sumerian clay tablets as T.
I took a quick look at your video which Audrey so kindly provided a link for and thought there might be one standing out from the crowd. But I could be wrong, of course.