I got fed-up with having no tiles so I made 'em myself! Not super-accurate but they do the job, I think you'll agree.
Artwork took about an hour or so then just printed on heavy stock - each time varying the hue/density/lightness/contrast.
4.5Mb file and it's not going to be around forever.
• 16 inches at 300dpi.
• Adjust 'Hue' to suit your print setup.
• Adjust contrast/brightness/saturation (small amounts) to get natural variations.
• Resize/resample to suit (10x10", 8x8" etc etc).
Don't expect super-accuracy but it's nice enough.
For personal use only - resale expressly forbidden.
Right Click> Save Target As...