Probably Cannibal Corpse as the most well-known but it is merely one's opinion.
Cannibal Corpse, easily.
Probably Children of Bodom. They are the most well known.
Possibly In Flames or Arch Enemy.
Anything by the band Gorgoroth, or any black metal band. Most Black metal/ Death metal bands come from Europe and usually have lyrics in Norwegian that commonly refer to Satan and demons, but do not use swear words.
though extremely overrated it`s children of bodom
In terms of record sales, most would probably list one of these Gothenburg/'Melodeath' bands, which really aren't Death Metal. As far as actual impact on the scene goes, it would be Bathory, who were basically the cog in the mechanism from which Death Metal bands developed in Europe (vs. American bands, who took their que from Possessed).
This question can be a bit more ambiguous than you realise. Out of all the band which played Death Metal, Sepultura would be it. However, none of the albums they released during their Death Metal period would be particularly high grossing albums. Out of straightforward, true-to-form Death Metal bands, who haven't deviated away from it, Cannibal Corpse would be the band. As for the so-called Melodeath bands, they're irrelevant.
Black Sabbath.The second was Metallica which is now and was the greatest metal band. Much as I love Metallica, I don't think they were anywhere close to being the second ever metal band. Plus after Black Sabbath there was the new wave of british metal such as Judas Priest, Iron Maiden, Motorhead, and more. Metallica and bands like Slayer, Anthrax, and Megadeth, started in the early to mid '80s.
I recently came across this band. Their name is The Berzerker and they hail from Australia. This is the fastest shredding band I have ever heard. They are twice as heavy as Slipknot and 4 times as fast. You can check them out on MySpace. I think they are the heaviest band I've ever heard and I've been a Metalhead for over 30 years( I'm 51 years old). The heaviest heavy metal genre is death metal and black metal or a subgenre of them such as brutal death metal. Doom metal as well can be quite heavy - especially funeral doom or death/doom which is often slower and "thick" sounding kind of heavy. I think Berzerker is fast and chaotic but fastest doesn't mean heaviest. It is all anyone's game as to what band plays the heaviest metal music and in the end all comes down to personal preference.
Slayer i guess
most of them are metal
Metallica