PBR Materials for Photorealism

Physically-Based Rendered materials or PBR materials are materials for 3D models that are based on scans from real life objects. They combine different types of materials, such as albedo for colour and metallic and normal maps to make an object look shiny, and textured.

THIS site is a great resource for many free, high-quality PBR materials for Blender, Unity, and Unreal.