"Underground sketchy stuff" and "the best the genre has to offer" aren't really mutually exclusive. The underground sketchy stuff is where a lot of the atmosphere is, once you get past the obvious stuff like Suffo/Cryptopsy.

Many countries have cool regional BDM scenes but they're hard to generalize in clean strokes other than, like, "Colombian bands tend to be really primitive and sloppy," "Germany tends toward a combination of slammy and technical," "NY is groovy," or whatever. But throw a dart at a map and it's safe to assume either/some combination of Suffocation, Disgorge or Devourment will be huge influences. So just look around and listen, look into some labels that were major players like United Guttural, (early) Unique Leader, Unmatched Brutality, Comatose, etc. That's my main advice.

Some 90s stuff you might have missed:

Fleshgrind

Pyrexia - if you like Suffocation a lot and want more like that.

Deeds of Flesh - not a huge fan of this band, but by most people's estimate they should probably be #6 on your list. Sort of the next truly influential longrunning American BDM band after Suffocation.

Mortician - love them or hate them, they left an impact.

Clean Flesh - "predator vocals" started here.

Afterbirth - their 90s stuff is partially to blame/thank for slam, along with Internal Bleeding and Repudilation.

Malignancy - quirky smartypants sorta technical band from the late 90s

...

Millennial stuff I like (not exhaustive):

Inveracity - Greek Suffocation worshippers. They don't play slam, but their incredibly knuckle-dragging, breakdown-focused debut album was probably a bit influential on millennial slam.

Severe Torture - sort of like a more BDM take on Cannibal Corpse. First two albums are good. Worth a shot if you wanna get away from some of the more off-the-wall stuff in the genre.

Mutilated - see above. Lots of CC influence in this obscure and generically named but great band. It's sort of funny being able to talk about Cannibal Corpse influence as if it's something that takes the edge off rather than adding edge, but that's BDM for you.

Condemned - sort of a Disgorge clone. They had Cephalotripsy's vocalist, so they have those BLURP BLURP BLURP OOWEEE vocals you'll either hate or love. First album's about as one-dimensional as music gets, the second album's a little more moody and "artistic."

Pathology - you can kind see this band's discography as a microcosm of how the genre evolved. No frills deathgrind type stuff with medical/gore lyrics at the beginning, but then in the late 2000s there was a slow shift into sci-fi themes (which was the trend at the time), goofy neon album covers, slam influences, etc. You could accuse them of trend-hopping, but they're decent and a useful signpost band if you're just now getting into the genre.

Prostitute Disfigurement - classic lowbrow, trashy BDM with better musicianship than you might expect. I like the darkly melodic Carcass-isms in their second album.

Brodequin - always lo-fi, (mostly) always blasting. Their medieval aesthetic was unique and they had great drumming, but sort of a challenging band to get into imo thanks to consistently dismal guitar sounds and a relative lack of breakdowns/"ear candy."

Cerebral Effusion - Spanish band.

Flesh Consumed - I always saw their first album as sort of the final statement on 2000s brutal death metal. It kinda does everything--it's morbid, creepy, technical (without getting TOO technical), and hugely slam influenced without actually being slam. Monolithic guitar sound to top it off.

Saprogenic - unique American band who somehow mushed together Covenant/Formulas/Gateways era Morbid Angel with Devourment, if that makes any sense. They had those broiling, imperialistic melodies that scream mid-career Trey Azagthoth, plus insanely triggered Sandoval-esque double bass very high in the mix, but they also had those BDM sewer vocals and they throw a big dumb stupid slam or two at you in just about every song.

Dyscrasia - one of those early (not 90s, but still relatively early) slam bands who were kind of an evolutionary dead end in that they have very little musical connection to modern slam. Groovy but they incorporated those grooves into some pretty complex/progressive song structures. Proudly refused to use triggers, for what it's worth.

Defeated Sanity - another band I'm not huge on, but they're the heir apparent of post-Cryptopsy technical stuff and hearing them is important to having literacy of the genre.

Despondency - I much prefer this German band over Defeated Sanity. A little more grounded and focused on midpaced nastiness. If Defeated Sanity is slam with an IQ of 180, this band is like slam with an IQ of 120.

Infernal Revulsion - Japanese slam band who (unlike a lot of slam bands) actually had riffs when they weren't slamming. Try the first album. note: their most recent stuff is awful and sounds like some sort of slick death metal-ized modern hardcore nonsense.

Degrade - a rare Swedish BDM band worth hearing. Their one album is about as generic as it gets, but it's very very heavy and lots of fun.

Corpulate - they did one album and I don't even know how to describe it. Mathy progressive slam? Crazy shit.

I'm partial to the early (VERY early) Goregrind sound, before goregrind got stale and, frankly, rather lame. So, I would put early Carcass up there. Bolt Thrower's third and fourth albums (Warmaster, IV crusade) are epically awesome.

I love Carcass and Bolt Thrower as much as the next guy. They are two of my all time favorite bands actually. But they have nothing to do in a thread about brutal death metal.

Well, as you said yourself... this answer depends on where we draw the line for brutal death metal. Bolt Thrower; I can see your point, they are heavy as shit but maybe not what one would call "Brutal Death Metal." If you define Brutal Death metal as having a lot of technical playing and complex structures, then some of the early Carcass albums would qualify- "Symphonies of Sickness" and "Necrotism" certainly. Even "Reek of Putrefaction" though that might actually fall more under goregrind than "brutal death metal." I understand the need for categorization of music, but so often it's so subjective and a matter of splitting hairs, or one's opinion, that I kind of hate getting into these kinds of arguments.

Aside from the newest record, pretty much everything Analepsy has done is top tier.

- Abominable Putridity

I was surprised no one except you mentioned them; among the new bands, they seem to be one of the most popular ones out there. I like their style; they remind me of Analepsy, they seem to be the forerunners of the new BDM scene that made slam what it is today.

Other two bands that I found and thought were pretty cool are Kraanium and Katalepsy, both with a capital K. They are part of the new school of BDM tho, not classics of the genre.

I was surprised no one except you mentioned them; among the new bands, they seem to be one of the most popular ones out there. I like their style; they remind me of Analepsy, they seem to be the forerunners of the new BDM scene that made slam what it is today.

Other two bands that I found and thought were pretty cool are Kraanium and Katalepsy, both with a capital K. They are part of the new school of BDM tho, not classics of the genre.

I don't wanna sound like a nerd but all those bands you mentioned are slam death, and not BDM

I thought slam death was part of BDM, like a micro sub genre of the already small genre that is BDM.

ROTTING - Crushed

Still imo one of the best BDM bands. Even if they only have 1 album it's still a banger and It is always in heavy rotation for me.

This genre to me is kinda frustrating because on paper it's everything I look for and it's even like my personality, completely over the top and deliberately trying to piss you off, but for some reason idk none of it really ever grabs me when I try to explore it.

Idk it's almost like there's just nothing below the surface at all.

I say that because I'm genuinely looking to see if anyone initially had this opinion but grew to develop a taste for it cuz to me it just seems to only be brutal in the literal definition of the word.

When listening to brutal death metal, it's important to understand that it's an acquired taste; you first have to listen to the albums and cross the line of thinking things like "this just sounds like noise" and try to listen to the melodies, the rhythms, and the songs that this bands creates. As you can see in this thread, there are multiple styles of brutal death metal, but I would say they can be summarized into three schools.

The first one is the technical one; this style is usually referred to as technical death metal. Not every technical death metal band belongs in the brutal death metal category, but some do, especially bands like Suffocation, Defeated Sanity, Deeds of Flesh, Nile, and Cryptopsy. Because those bands play their instruments in a very technical and progressive way, it could be a little hard to listen to them the first time you discover the genre. It is probably the most respected school of BDM in the metal community; most bands in this genre are pioneers of the scene and very respected musicians in their instrument.

The second one is the slam school of brutal death metal; the kings of this style are Devourment, no question about that. This style focuses more on slam riffs, death metal breakdowns, simple song structures, low-tuned growls with a lot of pig squeals, and trying to sound as scary as possible. This style usually merges with other genres like grindcore, deathgrind or goregrind. It's usually the nastiest form of brutal death metal and also the goriest one; when you think of brutal death metal, you are probably thinking about this style of music. There are pure slam bands nowadays that play a distinctive style of modern bdm; they kind of created a scene of their own, especially in Russia. Most of the bands that the guys recommend here belong to this school of BDM.

The third one and the one i discover in this thread is the hardcore one, specially the New York scene, there is one scene of brutal death metal that for me is different to the ones we mentioned, this are probably the first bands that mixed death metal with hardcore before the creation of deathcore. The band that gave origin to this scene is Suffocation, but most important bands of this style are Pyrexia, Internal Bleeding, Eternal Suffering, Repudilation, Broken Hope, Skinless, etc. They play a very primitive style of BDM; they were arguably the first bands, along with the technical BDM bands, to develop the genre. If you like New York hardcore, you will like this style. It has lots of groove-induced breakdowns and hardcore, bouncy riffs mixed with more street-wise lyrics talking about violence and crime in a NYHC way.