Have you looked at the Chaos Cosmos library that is included with V-Ray?
https://cosmos.chaos.com/assets/materials
You’ve got another sites offering PBR] like CGAxis - 3D models, PBR, HDRI for your 3D visualizations projects
Free resources such as
ambientCG - Public Domain Resources for Physically Based Rendering
Textures | cgbookcase.com
You could also look at Adobe Substance - that gives you access to procedural texture generation, which allows you to create almost anything and alter (often substantially) the textures they provide
They have over 11k assets which can be modified, giving you a near infinite amount of variety