Here you will find some sample materials for OSPRay path traced
rendering.

All textures used are creative commons (CC0) copyright (no rights reserved)

Link to textures found online and their CC0 source are below:
 Metal_brushed.jpg - https://cc0textures.com/view?id=Metal010 
 Metal_cast.jpg - https://cc0textures.com/view?id=Metal006 
 Solar_Panel_* - https://3dtextures.me/2019/09/06/solar-panel-001/ 
 Carbon_Fiber_* - https://3dtextures.me/2019/11/19/carbon-fiber-001/ 
 Plastic_White_* - https://cc0textures.com/view?id=Plastic010
 Plastic_Dark_* - https://cc0textures.com/view?id=Plastic011
 Plastic_Orange_* - https://cc0textures.com/view?id=Plastic007
 Fabric_Green_* - https://3dtextures.me/2020/02/04/fabric-polyester-001/
 Fabric_Orange_* - https://3dtextures.me/2018/10/25/fabric-006/ 
 Fabric_Tan_* - https://3dtextures.me/2019/01/21/fabric-burlap-001/ 
 Fabric_Camo_* - https://3dtextures.me/2019/07/30/fabric-camo-003/
 Camo_Mesh_* - https://3dtextures.me/2020/08/06/fabric-mesh-military-001/
 Camo_Dull_basecolor.jpg - modified from https://3dtextures.me/2019/07/30/fabric-camo-003/ 
 Cork_* - https://3dtextures.me/2019/02/14/cork-002/
 Particle_Board_001_* - https://3dtextures.me/2018/01/20/particle-board-001/ 
 Concrete_1_* - https://3dtextures.me/2018/08/28/concrete-011/ 
 Concrete_2_* - https://3dtextures.me/2016/08/27/c0ncrete-007-with-license-to-kill/ 
 Asphalt - https://3dtextures.me/2018/05/07/asphalt-005/ 
 Brick_Wall_1_* - https://3dtextures.me/2020/09/17/brick-wall-019/
 Brick_Wall_2_* - https://3dtextures.me/2018/04/23/brick-wall-010/ 
 Sand_* - https://3dtextures.me/2017/03/23/sand-002/ 
 Snow_* - https://3dtextures.me/2018/03/01/snow-003/ 
 Ground_Dirt_* - https://3dtextures.me/2019/10/21/ground-dirt-007/
 Ground_Wet_* - https://3dtextures.me/2020/06/01/ground-wet-003/ 
 Water_* - https://3dtextures.me/2018/11/29/water-002/ 
 
Additional Textures that were created by development team and are also CC0:
 checker.png - Created by Kitware within ParaView.
 METAL_scratched_* - Generated by Kitware from Allegorithmic's substance material: https://share.allegorithmic.com/libraries/1785
 Circuit_Board_* - Made by Marston Conti and is free to use for whatever purpose