also the whole opeth argument is kinda relevant to alot of bands. In mourning being an example here, but they cover ground which opeth generally dont tread, which is clear and concise songs. But i think with many early blooming bands, its hard to come into the game not wearing their influences on their sleeves. not a fan of the band btw, just an observation when listening.
But take a band like enslaved who, on paper, will do a similar sort of thing. Clean, heavy, clean vox, harsh vox, big epic songs etc. But actually there would be no mistaking either band when listening to them. akercocke are also another example that might be thrown into the opeth comparison bucket.