Textures.com – Originally CGTextures.com (back in 2005), offering 15 free images per day out of a library of more than 125,000.

Pexels.com – Offers free stock photos and textures out of a library of several 100,000 photos.

Blender Cloud Library – A cloud texture library for Blender licensed CC0.

Poliigon – Offers multiple maps in addition to the raw textures. Requires registration in order to access most of the content.

TextureHeaven.com – a texture collection by Rob Tuytel offering CC0 licensed PBR textures (as in made of multiple maps like poliigon)

SolarSystemScope.com – a solar-system-related texture website by space enthusiasts based on data from NASA.

HDRIHaven – a HDRI images collection by Greg Zaal, all CCo licensed.

TextureKing – a collection of a few hundred textures.

SweetHome3D – sweethome3d’s list of websites for textures.

Sirious sds’s texture packs – contains several texture packs, some of which are free.

Want your textures added to this list for free? Contact me.