Unity Asset Store - Unity's asset marketplace for game makers.
Seamless PBR Textures - Seamless PBR Textures is one of the intelligent software that utilizes physically based rendering technology that aims to simulate when light reacts with the model.
Kenney Assets - We've created over 40,000 images, audio files and 3D models for you to use in your projects. Thanks to our public domain license you're even allowed to use them in commercial projects!
Good Textures - FREE High Quality Textures for personal and commercial use
GameDev Market - GameDev Market is a marketplace for high quality, affordable 2D, 3D, GUI & Audio game assets, handcrafted by talented creators around the world.
3DJungle - 3DJungle is a software that contains attractive tileable textures, 3D models, materials, and lessons for 3D designs and visualization, making you easily apply any texture in your models without any hurdle.