There are plently of brilliant Czech extreme acts around. The scene if completely overlooked. In my opinion, Czech bands are much more talented and original, than those from the overrated Polish scene.
ROOT and MASTER'S HAMMER are two great cult bands indeed, and a prime example of completely overlooked Gems.
Here some other worth seeking at any cost (for those who are into more "extreme" metal:
AMON GOETH
MANIAC BUTCHER
DARK STORM
AVENGER
ENTRAILS
ASMODEUS
BIG BOSS
etc...