Mod theory

I've always been impressed by the talent of certain players, the ability to change for the better aesthetic parameters of certain games.
Many times it happens to see titles that do not fully convincing, but only for aesthetic reasons.
The gameplay this time has nothing to do.
However, it seems that has someone already worked.
In the links below, you will find several games that maybe mod can return useful.
If you own one of Fallout (HERE),  Oblivion (HERE), Skyrim (HERE), Street Fighter 4 (HERE) in these links you will find everything. (¬‿¬)
These are just a few, but if you search on the net you can find more.