I spend quite some time finding something like this but most times come across marble slabs …
https://www.cc0textures.com/view.php?tex=Tiles17
https://www.cc0textures.com/view.php?tex=Tiles18
https://drive.google.com/drive/folders/0B4hOzd4dOChqaEhvaFB1STRzUXM
https://drive.google.com/drive/folders/0B4hOzd4dOChqZHkwcEk4SVRtcGs
I’d grab any high-res seamless texture with a pattern that is kinda sorta lookalike. Then recolor and albedo match to the material I’m going for using procedural approach. Finally I’d tile them procedurally. If the tiling pattern is hard to recreate procedurally, you can create mask image textures; one for grout mask and one with random colors on each tile. These colors can be added to the texture coordinates, scaled, skewed, and rotated to create a pretty good texture that doesn’t look like obvious repeated CGI.
Maybe this will help you, although I don’t know if you’re willing to sacrifice time for memory. I haven’t done an elongated herringbone pattern - maybe that’ next on my list