What are some bands you believe shared some sort of musical or chronological bond that you would put into a group of four? Previously mentioned examples include the big four of Grunge ( Nirvana, PJ, Soundgarden, and AIC), and the big four of metal, or thrash metal, or whichever it is (Metallica, Anthrax, Slayer, and Megadeath). I always make a big four out of some of the most popular AOR bands, Styx, Foreigner, Journey, and REO Soeedwagon.