From the Tutorial on how to build Bronze Silver and Gold Rarity glow, perfect for your custom characters!  Works in performance mode as well
These only currently work on CUSTOM CHARACTERS inside UEFN, you cannot currently access player models/materials to apply these.
Install by Creating a new project and dropping the files into the content folder in your windows explorer, you may need to reopen UEFN after adding files

 
Tutorial Link:
 
Metal Rarity Glow Character Effects – UEFN Tutorial

Contains:

Unreal Engine Version: UEFN ONLY
UEFN Version: 36.20
Master Materials: 2
Material Instances: 5
 
Component Assets:

Materials: M_Metal_Glow_Base