Yeah, there are tons. This is not really a valid question.
As far as metal bands that were particularly influential, a few that I would list would be:
-Maiden, obviously. Along with Priest, they epitomized the NWOBHM movement.
-Y&T: Probably not influential on a world-wise basis, but they were hugely influential on the California rock and metal scene. Most of the bands that came up in the late '70s and '80s in SF and LA (and Sac) opened for them at one point or another and/or cite them as an influence.