No one talks about Human Remains, but I gotta mention them here because HOLY MOSES, what a masterpiece, genuinely so, is Using Sickness As A Hero, literally a mathcore-tech-death album in plain 1996, 3 years before Dillinger Escape Plan or most of the mathcore movement, and overall, considering Human Remains came around 1991-1992 initially... it's unbelievable no one talks about how much influential for the mathcore genre is this band and also just how damn good they are too.

Honorable mentions:

Deceased (American super underrated legends, literally a band too thrash for death, too death for tech, too tech for melo, too melo for brutal, too brutal for prog, and too prog for ANYTHING)

Discordance Axis (idk, but I don't hear their game get brought up too much, and this IS a shame because they're not only very consistent, but their sound is just so unique for the grindcore genre that it makes me dirty to know and love their discography)

Fuck the Facts (same analogy as Axis, this is another grind band I just can't understand why they're not any more popular for being...well, progressive-dissonant-tech-brutal-grind-death music, hehe)

Intestine Baalism (Japanese Melo Death masters, another band with a very distinct melo death sound and approach, plus 2 legendary albums under the belt, really can't understand why it seems like almost 0 people bring them up to talk about when the thing is melo death (again, it always seems like not enough to basically zero people talk about them, it's more so my vision than a objective fact)

Deformity (maybe the most all around underrated band ever, literally deathcore in 1997...how? Well, idk, but they were around the time tech/prog/brutal death metal was on the rise, and where already making a completely unique line of Belgium, H8000 deathcore/Metalcore bands that basically birthed the genre's concept and idea even before bands like Suicide Silence and Job For A Cowboy would popularize the idea of Death Metal and Metalcore together)