They were created by Joe Kelly when he was writing Action Comics in a story called "What's So Funny About Truth, Justice & the American Way?" (Action Comics #775 to be exact), which was Kelly showing his frustration with how the anti-hero (specifically The Authority which was the rage for comic fans at the time) was being overhyped and straightforward old school heroes like Superman were seen as lame by comparison. They were killing villains and rubbing it in Superman's face that he was out of touch and his methods didn't work and they were the new wave of super-heroes but ultimately Superman showed them that having a "by any means necessary" attitude made them villains not heroes. The story was named the #1 comic of the decade by Wizard Comics.
So the team is:
Manchester Black (team leader): A white Brit with telepathic/telekinetic powers
Coldcast: A muscular black dude who had electromagnetic powers
Menagerie: A Puerto Rican chick who could transform into alien creatures
The Hat: Asian dude with a magic hat
The story that they were introduced in was named the made into an animated movie called Superman vs The Elite (that stayed very close to the source material) which has one of the coolest Superman scenes to ever appear in a movie: