I forgot about the extreme metal sub genre Napalm Death,Carcass,and even Demoniac

maybe if you talk more into detail like skyclad the first folk metal.Power Metal bands like I am I Dragonforce and Power Quest.and a ton of thrash metal bands like Xentrix, Onslaught, sabbat for heaven sack didnt even mention Vemon?well these guy are know for being scottish but i will say their name Alestrom and Gloryhammer

https://soundcloud.com/ironagerecords/sets/behind-closed-eyes-album-by

The beatles were not metal!

The Beatles ???????????? o_0