Blender Sphere - PBR (Physically Based Material)
This blender file (2.79a) contains 3 spheres. One is Metallic, One is Di-Electric and one is Rough. You can expand the node trees to see the IOR and other settings and material setup. If you like it, do share and help out a budding developer.
No plugins required.
This is a basic UV unwrapped sphere with a dielectric material I built based on Blender tutorials and is accurate for a PBR workflow in Blender and cross tested from various resources I've checked.
If you feel confident of building this yourself, drop me a message and I'll guide you to the learning resources.
The HDRI environment map is not included and you'll have to source that for yourself. If you need pointers, drop me a message and I'll be glad to help you.
You can get the HDRI images for the environment textures from here: