This is my type of thread! I love this stuff!
Most of my favourites are the more popular bands (Warbringer, Evile, etc.), but I'll share a few most people might not be familiar with:
Mass Extinction - Creation's Undoing
This is a pretty cool band out of Ireland. To my knowledge this demo/EP was their only release, and while not overly convincing, it is fun to throw on once in a while.
Bludvera - Terrorform
These guys are driven by the insanely awesome vocals of Scott Clayton! They have plenty of good riffs, but the style of thrash is fairly standard. The only bad thing about this band is their refusal to re-record their best song ("Infection" was only released a two-song demo rehearsal that I don't think is available any more).
Fatality - Beers From The Grave
This is a local band for me, and they are just preparing for the release of their second record, Psychonaut, but their first album is well worth hearing. Their singer is the only guy I've heard that comes close to John Connelly in Nuclear Assault. The songs are so catchy that they'll be stuck in your head the first time you hear them. I'm not that keen on what I've heard from the second record, but I'll definitely give it a shot.
Mutant - Laserdrome
If you only listen to one band in this thread, it should be Mutant. After releasing one of the most brilliant four-song EP's this band seems to have fallen off the map. Their songs are the perfect mix of technical riffing and headbang-inducing moments. In fact, it's been way too long since I've heard the EP, and will be busting it out today
I'll also just namedrop a few of my other favourites in case anybody needs more bands to check out: Alcoholator, Laceration,
Invection, Mortifier (first album), Besieged, Fog of War,
Insinnerator, Pollution, Entrench, Vindicator.