So many sub-genres, and each has it's distinct sound.
In the late 80's-early 90's, I actually couldn't stand too much outside of Iron Maiden or Judas Priest (both great bands).
I tried to listen to Celtic Frost, but it was Cold Lake, and album most CF fans derided, but the band does some different stuff over the course of their history. I own all their albums now and enjoy them a lot.
My tastes have changed quite a bit since I first heard symphonic metal around 2007 and I've given different metal genres more of a chance since.
If you like early Metallica, then Slayer, Testament and other thrash metal bands would be good for you. Metallica has changed up their style a few times, but the other bands, not so much, so they're still closer to that style.
Doom metal is another pretty good way to go. I've gotten huge into Draconian, in no small part because of the second, female vocalist. But they're heavy and doomy and on their early albums somewhat reminiscent of Sabbath.
Folk metal bands like Cruachan and Eluveitie are another way to go, especially if you love Celtic music and metal. I don't own any Cruachan, but do own all the Eluveitie albums.
It's hard to jump right in. Do what I usually do and find videos or at least audio tracks on youtube, check out different bands and decide what you like well enough to buy.
