EDIT: Found this on amazon: https://m.media-amazon.com/images/I/61HP3WhF05L._AC_SL1200_....
Not sure what to think about that one, though.
https://www.techradar.com/news/computing-components/peripher...
Hexagonal keys might provide more accuracy, as they approximate circles more closely while still tiling, but they are going to waste some space at the edges of the area.