Def Leppard (first 4 albums), although, I consider the limit of DL is the Hysteria album !
Saxon - almost all of the 80's albums (Wheels of Steel, Strong Arm of the Law and Denim and Leather are all classics), but they also continued to release quality new music.
But there are also other great NWOBHM bands that don't have much success like Maiden, Def Leppard and Saxon:
- Angel Witch, White Spirit, Praying Mantis, Raven, Samson, Tygers of Pan Tang, Urchin and so on....