Love some old school thrash. Testament, Exodus, Razor, Forbidden, Annihilator. There’s some great stuff from that era that leans on the more progressive side as well, like Toxik or Voivod. Vektor is a newer band that goes in the direction of prog thrash, but also has some killer Chuck Schuldiner-style vocals. I’d also recommend Exmortus. They’re a bit more straightforward, but have a Yngwie Malmsteen/Neoclassical flavour to them, while still keeping the thrash riffage. As far as tech death, I’d recommend the first 2 Cryptopsy records, “Blasphemy Made Flesh” and “None So Vile”, Dying Fetus, and pretty much all of Death’s discography. Their earlier stuff is a bit more palatable if you’re into 80s thrash, but it’s less technical than their last few albums.