Quartetto has an aged white, and aged black, that look fantastic together in a checkerboard pattern. They really look like they could have been there a hundred years, when you have a good installer. https://www.daltile.com/products/Concrete-Look/Quartetto It's not marble look, but it's better than marble look.

For those confused about the difference between harlequin and checkerboard, harlequin uses actual diamond shaped tiles. Diamonds are not squares. They are parallograms.

A chevron is longer parallelogram, with the angled ends.

A checkerboard of squares, set on the diagonal, can appear to be diamond shaped, because of forced perspective. But it is NOT a harlequin pattern.

Thanks for the education! I guess I'm actually looking for square tiles to be set at a diagonal. Any insights to share on the initial request?

8x8 Is an uncommon size, except for cement look tiles. Move up to a 12x12, and your choices will greatly expand. I've used Perpetuo, mentioned above, many times. It's a great choice. It comes in matte or polished.

Hexagonal tile instead?

• Merola Tile Classico Carrara Hexagon 7 in. x 8 in. Porcelain Floor and Wall Tile (various options)