This is an augmented version of the assets naming convention recommended by Epic for the files of your UE4 projects.
The original version can be found on the Assets Naming Convention Wiki Page

All files are named in UpperCamelCase, with an underscore as word separator (Prefix_)AssetName(_Number)(_Suffix)
Example:
T_Rock_01_D

Prefixes

by usage (optional because of filters in content browser)

by type

for Textures

Suffixes

for textures

for meshes

for animations

for Dungeon Architect plugin

Other Types

Notes: Maps/Levels have no Prefix, but _MUSTALWAYS be placed in a "Maps" folder.