They been around since the early since 1991, so it’s hard to pick. I do think some albums have songs that sound Metallica like, and you can tell when nu-metal started just by going through their albums. One oddity, the singer says digital ruins their sound, so they still record in analog.
I’d check out Ten Ton Hammer, Crashing Around You, Davidian, Bulldozer, and whatever comes up when you search. PowerMetalHead might become a Machine Head fan. Let me know what you think.