It's basic metal knowledge that The Big Four is Metallica, Megadeth, Anthrax, and Slayer...but if the metal scene was to dub a modernized Big Four, who would it be? This is my opinion.
I know all the oldheads are going to want to tear me apart in the comments for this one, but just hear me out. It's a no brainer that Metallica, Megadeth, Anthrax, and Slayer make of The Big Four, because of their gigantic influence on the genre and making metal what it is today. This is just my take on who would make of The Big Four if it was created today.
There is going to be so many people that disagree with me on this one, but you can't deny how big Slipknot has grown in the past decade. They started out some small underground experimental metal band in Iowa, before blowing up and having a whole metal festival named after them (Knotfest). They basically fronted the Nu-metal wave in the 2000s, taking in influences from death metal, metalcore, speed metal, and experimented with a ton of stuff like rap and hip-hop while throwing in some old school rock ballad-ish stuff in there too.
They're one of the very few modern metal bands to receive a Grammy, and when you can get a mainstream media award show to notice your talent, without selling out, then you've got something going on.
Unlike the last one, I know everybody can agree with me on this. No words can describe how incredibly awesome this band is. They created the perfect harmony between death metal and black metal and morphed it into something that sends chills down your spine every-time they play. Their lyrics and appearance tend to lean more towards the darker and satanic side of things, but whatever your stance is on that they still deserve to be on the list for the amount of talent they have and their influence in the genre. They are the gods of blackened death metal.
Everyone has huge respect for them, but Gojira has been around long enough that they really should be more highly regarded. If you want to talk experimental, they're listed as a technical, death, progressive, groove metal band. In my personal opinion though, it doesn't matter what sub-genre a metal band is if they're good, and Gojira is just plain good, no other way to put it. I remember the first time listening to Gojira, and I was completely blown away. In all honesty, I have never heard another metal band like them before. If you're a new metal listener, this is the perfect band to dip your feet into and be able to explore the genre a bit more.
(I'm sorry I have to) Suicide Silence is the band that shall take the number-four spot on this list not only for the talent and brutality they possess but also for the mark that they have left on the deathcore scene of today (RIP, Mitch). Suicide Silence may be past their heyday, but they've definitely influenced the new wave of deathcore bands across the world, and that is something to take notice of. Before Mitch Lucker passed away, Suicide Silence was on top of the world and was a staple piece of the metal community at the time, so it just feels right to place them on the list.
Honorable mentions: Thy Art Is Murder, Chelsea Grin, Amon Amarth, Cannibal Corpse, Meshuggah, Born Of Osiris, Whitechapel, Lamb of God, Avenged Sevenfold, Korn, Asking Alexandria (not really), Bring Me The Horizon (take a wild guess), Motionless In White, The Amity Affliction, and many many more bands that dedicate themselves to doing what they love and expressing themselves through music.