Elder Races And Law Enforcement

In the Green Lantern superhero comic book, the Guardians of the Universe are an elder race that organizes the Green Lantern Corps as a multi-species, intergalactic law enforcement agency. The Guardians combine aspects of the Others in Poul Anderson's The Avatar and of the Danellians in Anderson's Time Patrol series. 

The Others are a cosmic elder race that facilitates travel through space-time by less advanced beings but that rarely has occasion to intervene in the affairs of such beings. Law enforcement is not necessary. The Danellians, an elder race in time as opposed to space, are our successors rather than our predecessors. They do have to intervene in the affairs of their ancestors and therefore organize the Time Patrol as a time travelling police force to prevent interference in past events.

Another possible comparison is with EE Smith's Arisians organizing the Galactic Patrol against the Eddorians but that is hardly on the same level of writing. 

When a human spaceship rotates around a T machine constructed by the Others and arrives at a time before the galaxies had condensed, Poul Anderson brings home the implications of the concept of a species operating on the scale of cosmic space-time.

Guardians and Arisians: space.

Danellians: time.

Others: space-time.