What were the names of different generations of actors?

I know that there used to be a generations of actors called the rat pack, and that through the years many celebrities have played on the concept. For instance, the brat pack for young actors in the eighties and the frat pack for a group of comedian actors in the 2000/. Even George’s Clooney ocean movie’s succeeded in part because of the association that generation of actors were able to create between themselves and the rat pack. But what other names have been used to describe different generations of actors.