A civilization in possession of energy at the scale of its own galaxy, with energy consumption at ≈4×1044 erg/sec. Lemarchand stated this as a civilization with access to the power comparable to the luminosity of the entire Milky Way galaxy, about 4×1044 erg/sec (4×1037 watts).
Examples of Type III Civilizations
In these examples, the exact power consumption of their entire civilizations is often unknown. They are estimated to be type III based on the scope of their influence and technology. IE, civilizations with FTL drives and control over entire galaxies, or with abilities to affect the universe on the planetary scale.
The Maltusians of Oa (including the Guardians of the Universe and their agents, the Green Lantern Corps)
Grox - Control thousands of star systems surrounding the center of the Milky Way Galaxy.
The following examples are a different type of civilization from the ones previously mentioned. They are likely to no longer have physical bodies, having converted themselves to energy or other noncorporeal forms, allowing themselves to somehow influence entire galaxies.
Asgardians from Marvel Universe.