Pulled a 1-of-1 from a jumbo pack of 2019 Topps - #279, Rhys Hoskins. The only thing is that I have no idea what makes it "special" other than the 1/1 stamp on the back.
Fortunately, I also pulled a regular Rhys Hoskins, so I was able to compare the two. And, frankly, except for a slightly darker border on the front and the 1/1 stamp on the back, I can't tell any difference.
It's cool to pull a 1-of-1, but in the case of this particular card... what's the deal?
(In the below image, the 1-of-1 is on the left, and the regular card is on the right. In the scan, I can see that the image is darker on the 1-of-1, but the difference doesn't seem as pronounced to me on the actual cards.)