For thrash, I assumed you've come across the big four already (i.e. Metallica, Megadeth, Slayer and Anthrax). If not, have a look at them. Anything else from the genre, I suggest having a look at Kreator, Sepultura (pre-Chaos AD) and Exodus.
For power, have a look at the following (if you haven't yet):
Angra
Alestorm
Blind Guardian
Edguy
Falconer
HammerFall
Helloween
Rhapsody
Sonata Arctica
Stratovarius
Murray
What have you listened to from those genres already?
DocSprite
Dragonforce, Kamelot, and Dream Evil I have listened to a loy, and not much from thrash.