I use amazing Cyrodiil ENB by montegris and have one little visual issue - light beams in dungeons are too bright. It doesn't look realistic and breaks immersion for me.
This retexture was made to solve the problem. The textures are darker than vanilla ones, so light beams become soft and pale and look much better with ENB.

UPDATE: Added optional textures for vanilla dungeon mist clouds (made by request).

NOTE: This mod isn't for vanilla Oblivion setup. Light beams and dungeon mist with this retexture will be almost invisible in vanilla game without ENB.

INSTALLATION:
Unpack the archive and drop Textures folder to your Oblivion/Data. Merge folders and overwrite files if needed.
Use Archive Invalidation function of OBMM.