There’s quite a lot of metal bands who have evolved into, what are now, completely different sounding bands. One example is Enslaved, who have incorporated a lot of Pink Floyd. Devin Townsend has changed from extreme metal to prog rock.
One big one that affected me at the time was Corrosion of Conformity, who changed from hardcore punk to stoner rock. They did it very well, fortunately. Neurosis also changed quite a bit between The Word as Law and Souls at Zero.
More famously, Celtic Frost suddenly went from proto-death metal to glam metal on Cold Lake. Mastodon are also another band who sound quite different now, compared to their first couple of albums, although still recognisable.