I wrote a little writeup a while back on essential classic death metal- it's really incomplete, but maybe it'll help you. Formatting is going to get really fucked up since it's a copy/paste. When you're done with them, just use the MA's built in "similar artist" feature for the ones you liked the most! You can PM me too if want more personalized recommendations.
Possessed (San Francisco, California): One of the first and most influential of the bands playing the extreme thrash that would evolve into death metal in subsequent, Possessed's 1984 demo, "Death Metal," was not only one of the earliest and most influential extreme releases, but is often credited (to limited controversy) as naming the genre itself. Their 1985 release of "Seven Churches" was a landmark in extreme metal that's hailed as one of the most influential of all time and is sometimes called the first death metal album.
Recommended listening: Seven Churches (1985)
Master (Chicago, Illinois): Early brutal thrash prelude to what would become death metal. They had a punishing album recorded as of 1985 but that was shelved due to conflicts with their record label (though it was still heavily distributed by tape traders at the time), and instead debuted with a 1990 self-titled album. Notable also for heavy overlap with legendary death metal band Death Strike's debut, with Fuckin' Death sharing many songs with early Master material due to Mittleburn and Speckman's involvement in each.
Recommended listening: Unreleased 1985 Album (2003), Master (1990)
Death (Altamonte Springs, Florida): Another early influential band that sometimes gets credit for naming the genre. Started off named "Mantas" before changing their name to Death, and released several thrashy demos in between 1983 and their first album in 1987, with the most notable of the demos being the "Death By Metal" tape. Their debut album, 1987's "Scream Bloody Gore", is considered by many to be the first death metal album by the people that aren't calling either Seven Churches or Necrophagia's debut the first death metal release. Primitive, fast, and obsessed with death, the early Death material is the blueprint of much of the earliest death metal to come into existence, and many members went on to form other incredible bands. Albums following 1988's "Leprosy" became more technical and progressive, and are influential on those subsections of the genre; fan favorites from the later era are 1991's "Human" and 1995's "Symbolic".
Recommended listening: Scream Bloody Gore (1987), Leprosy (1988), Human (1991)
Morbid Angel (Tampa, Florida): Another band from Florida. Their debut wasn't the first piece of death metal to mark a significant departure from the genre's thrash roots, but it's certainly the most popular early release to do so. Its influence can be felt everywhere on death metal; swirling Satanic chaos is the order, and 1989's "Altars of Madness" is the delivery. They made heavy use of minor key tremolo picked melodies, and the way that they used power chords was heavily copied by later bands. Several of the songs from their first two albums are are rerecorded from their original debut, which was shelved for some time after an altercation between Morbid Angel's original guitarist and drummer. Their fourth studio album, 1993's "Covenant", is also notable for being one of the first popular death metal releases that was significantly downtuned.
Recommended listening: Altars of Madness (1989), Blessed Are The Sick (1991)
Bolt Thrower (Coventry, England): Bolt Thrower started off as a aggressive, grinding monster with 1988 debut "In Battle There Is No Law!" but quickly became slower and more crushing with future releases. 1989's "Realm of Chaos" had dropped a lot of early punk influence, and was the last record of theirs to heavily feature it. By 1991's "War Master" they had settled into the mid to low paced style that they're known for today.
Recommended listening: In Battle There Is No Law! (1988), Realm of Chaos: Slaves To Darkness (1989), War Master (1991)
Pestilence (Enschede, Twente, Overijssel, Netherlands): Starting off as a thrash band and changing to death metal after their debut, 1989's "Consuming Impulse" was influential not only on later death metal guitarwork with heavy emphasis on chromatic chugged rhythms and sharp leads but also on their vocals, with the album's vocalist Martin Van Drunen being one of the most revered death metal vocalists of all time. Followup albums were increasingly progressive.
Recommended listening: Consuming Impulse (1989), Testimony of the Ancients (1991)
Autopsy (Oakland, California): Formed by former Death drummer Chris Reifert, Autopsy heavily influenced and defined early death/doom with their demented, filthy mess of slow early death metal on their 1989 debut "Severed Survival". While most bands were pushing to be more intense than their contemporaries with fast tempos, Autopsy was going the opposite direction with slow ones.
Recommended listening: Severed Survival (1989), Mental Funeral (1991)
Obituary (Gibsonton, Florida): Yet more Floridian death metal. Obituary took heavy influence from Celtic Frost to present brutal slabs of death metal that alternated between many Frost-esque mid-paced sections and ripping thrashy ones. Viscerally filthy and always complimented by now-legendary vocalist John Tardy's often unintelligible slurred gutterals, 1989's "Slowly We Rot" was one of the most brutal releases of the '80s.
Recommended listening: Slowly We Rot (1989), Cause of Death (1990)
Entombed (Stockholm, Sweden): An early innovator in the Swedish death metal sound as Nihilist, Entombed's chainsaw guitar tone and aggressive riffing influenced waves of bands to come. 1990's "Left Hand Path" is one of the definitive Swedish death metal albums, and 1993's "Wolverine Blues" is widely credited as the first Death 'n' Roll album.
Recommended listening: Nihilist (1987-1989) (Nihilist demo compilation 1987-1989), Left Hand Path (1990), Clandestine (1991)
Deicide (Tampa, Florida): Originally named Amon and put out two demos under that name before changing their band name to Deicide. One of the absolute most popular death metal bands to ever exist; their first two studio albums are an exercise in Satanic excesses, chunky groove, sharp leads, tremolo picked rhythms, and Glen Benton's hateful vocals. 1990's "Deicide" was mostly rerecorded '80s demo songs from the Amon name and its followup consisted of more new material written specifically for Deicide.
Recommended listening: Deicide (1990), Legion (1992)
Nocturnus (Tampa, Florida): Nocturnus is best known for their contributions to early tech death and for having quite possibly the heaviest keyboard usage of their time, along with their connection to Morbid Angel by way of being formed by former Morbid Angel drummer Mike Browning. Their 1990 debut, "The Key" is a keyboard-laden and technical concept album, and their innovations in atmosphere in a death metal setting were extremely important to the development of the genre.
Recommended listening: The Key (1990)
Suffocation (Long Island, New York): The origin of brutal death metal, Suffocation's first EP was the first CD ever released on Relapse Records, and 1991's "Effigy of the Forgotten" is widely recognized as the first brutal death metal album and was immediately widely copied throughout the New York death metal scene. Featuring some of the lowest gutteral vocals yet recorded in death metal, Suffocation's heavy emphasis on tempo changing was uncommon at the time, and their love of chugged low-string breakdowns was quickly adopted as a hallmark of the upcoming brutal death scene.
Recommended listening: Human Waste (1991), Effigy of the Forgotten (1991), Breeding The Spawn (1993)
Immolation (Yonkers, New York): The sound of early Morbid Angel taken to their chunkiest chromatic extreme, with a massive guitar tone, complicated drumming, and the bestial roar of bassist Ross Dolan. 1991's "Dawn of Possession" was a New York take on a classic sound, and is another of the most important classic death metal albums of the early years of the genre. Later albums dropped some of the fury of Dawn of Possession to become more dissonant, creepy, and angular, punctuated by massive grooves.
Recommended listening: Dawn of Possession (1991), Here In After (1996), Close To A World Below (2000)
Incantation (Johnstown, Pennsylvania): The progenitor of the now popular cavernous death metal style, Incantation's 1992 debut, "Onward To Golgotha" is slow, massive, and murky, with an emphasis on alternating lower-string tremolo picked rhythms and higher melodies punctuated with pinch harmonics. Recommended listening: Onward To Golgotha (1992), Mortal Throne of Nazarene (1994)
Demigod (Loimaa, Finland): Finnish death metal's off-kilter melodies and emphasis on the low end really shines through in Demigod's 1992 debut, "Slumber of Sullen Eyes". They codified the odd Finnish death sound, and their sound can be found in a tremendous number of bands following them.
Recommended listening: Slumber of Sullen Eyes (1992)
Guitar/vocals for Draghkar (death metal). Demo tapes forthcoming on Witchhammer Productions.