Textures and materials

Public Domain / Creative Commons / Free

PolyHaven

ambientCG

CGBookCase

MaterialX Library (AMD)

3dTextures.me

FreePBR

ShareTextures

3D Jungle

TextureCan

CGAxis (free)

NO Emotion HDRs


Other licenses

The Textures Resource

Quixel MegaScans

Poliigon

Textures.com

Tileable

CGAxis (paid)