Substance Designer Community Wiki
Allegorithmic (@mattershots) • Instagram photos and videos
https://80.lv/articles/tips-tricks-on-reference-research/
Textures for 3D, graphic design and Photoshop!
https://www.flickr.com/photos/tjframe/sets/72157605581901392/
https://beta.mattepaint.com/gallery/
https://www.reddit.com/r/EarthPorn/
https://www.poliigon.com/search
Image * After : textures : walls
Free textures for 3D modeling, design and game development
Texture Ninja - high resolution textures
https://magazine.artstation.com/2018/08/environment-reference/