In the same vein as The Beatles, give Eric Clapton a listen. He has directly influenced an incredible number of artists. He was in a few bands, notably Cream.
Some of these artists class themselves as strictly metal, but it's still a branch of rock and should be known regardless
-Van Halen
-Motley Crue
-Black Sabbath
-
IRON MAIDEN
-Bon Jovi
I can't think of any to add at the moment...*hangs head in shame*
edit: for blues, look up some of your favourite artists and see their influences. The Rolling Stones/Clapton all list artists like BB King, Chuck Berry, Howlin' Wolf and Muddy Waters, but I don't know if you want to go back that far...