Travis Davids has recently released a new pack that features 100 tileable displacement/alpha patterns, tutorials, and other content.
Categories of displacement:
Every displacement map has been created as a 16-bit tif to ensure high-quality displacement results. There is also a normal map version included for every displacement.
These displacement patterns are useful for quickly detailing simple geometry or adding more complex surface detail to your 3D models.
You’ll also gain access to a fully narrated video tutorial showing you how to create your own tileable displacement/alpha patterns.
You can find more details here.