They're called super-teams, such as the Avengers, and the Justice League.
The LXG's are all literary characters or adaptations of the turn of the century; we would need to pick a genre.
For instance, a League of Extraordinary Gentlemen of 1980's TV might include McGuyver, Colt Seaver ("the Fall Guy"), Thomas Magnum (of "Magnum, PI"), and T.J. Hooker.
An LXG of 1970's TV might be Freddy Prinze (in ultra-cool format), Columbo, Beretta, and Carl Kolchak ("The Night Stalker").
So pick your Genre and Go!