Heavy Metal majors with independent debuts?

What are some of the most desired independent debut albums by metal bands who later went major? Any era. Specifically, ones that weren't reissued/remastered or if they were, are out of print and still rare.

I noticed that the 90's was the hot spot for self-produced releases, any genre. Tapes and CDs could be produced in bulk for as cheap as $1000. Many artists that hit it big, from Hootie and the Blowfish to Evanesence, had indie releases that are now elusive as hen's teeth. It was either because the internet was not mainstream yet or that the iTunes era hadn't come into play. Everything was promoted locally for these kinds of releases. But what metal bands have sought-after works in this category? Of course, I'm talking about those who eventually got signed.

Pantera.