These are some of the example pieces I have put together in Unreal Engine for various material classes I have taught.
A fairly lightweight magic orb material which utilizes the lowest cost noise node.
A two-sided shield material which demonstrates some concepts related to panners, refraction and opacity in UE4.
This effect is created by moving two panners across one another with a clouds texture and lerping it together with the UVs.
This is an example of how to utilize up-vectors and would be scripted to create procedural environments.
This is a window material that does not use an interior billboard and creates pseudo-refraction by LERPing the UVs with the normal map.
With all textures channel packed into 3 instead of 6 texture samples (along with no transparency / overdraw) you end up with a material that reduces vertex complexity by 90% and pixel shader complexity by 20% on a single draw call.