I saw  adaeha do this alittle while ago so I figured I'd share my favorite 50 bands/artists as well. The order isn't exact since I had a very hard time choosing everything's order after the top 20 or so.

50. Devin Townsend - Canada - Progressive metal, industrial metal, extreme metal, ambient, avant-garde/experimental


49. System of a Down - USA - Alternative metal, progressive rock, hard rock, experimental


48. Rage - Germany - Power metal, speed metal, heavy metal, symphonic metal


47. Bathory - Sweden - Black metal, thrash metal, viking metal


46. Avenged Sevenfold - Heavy metal, hard rock, metalcore


45. Dayglo Abortions - Canada - Hardcore punk, crossover thrash


44. Edguy - Germany - Power metal


43. Evanescence - USA - Alternative metal/rock, symphonic metal/rock, gothic metal/rock


42. Disturbed - USA - Alternative metal, nu/heavy metal


41. Dream Theater - USA - Progressive metal


40. Dir en Grey - Japan - Experimental metal, alternative metal, progressive metal, death metal, nu metal, metalcore, hard rock
https://youtu.be/XHnwGx_MGMA

39. Outworld - USA - Progressive metal
https://youtu.be/JtNF-90aqyg

38. Eumeria - USA/UK - Progressive metal
https://youtu.be/27dDga7gDcw

37. Megadeth - USA - Thrash metal, heavy metal, hard rock
https://youtu.be/SGagJervtMc

36. Dio - USA - Heavy metal
https://youtu.be/nfh7to0dmco

35. Girugamesh - Japan - Nu metal, alternative metal, alternative rock, industrial metal/rock, metalcore
https://youtu.be/pS7JwtUFUMg

34. Guns N' Roses - US - Hard rock
https://youtu.be/VC9L-BZ1PI0

33. Linkin Park - US -Alternative rock/metal, nu metal, electronic rock
https://youtu.be/GLQs0OrHiPY

32. Mantas (Death) - US- Death metal, technical death metal, progressive metal
https://youtu.be/h8g5QsT-RSw

31. Judas Priest - UK - Heavy metal
https://youtu.be/2IqyAhZtZ1c

30. Rush - Canada - Progressive metal/rock
https://youtu.be/Vf8jvSPA3XQ

29. Nocturnal Rites - Sweden - Power metal
https://youtu.be/fkuEjz3IkiQ

28. Unlucky Morpheus - Japan - Touhou Metal, power metal, neo-classical metal, melodic metal, symphonic metal
https://youtu.be/thDHCcOvD_g

27. Wolf - Japan - Heavy metal
https://youtu.be/2Dnagqj3Qo4

26. Wolf - Sweden - Heavy/power metal
https://youtu.be/yyPG0Ohl8g8

25. Faith No More - US - Alternative metal, experimental rock, funk metal, avant-garde metal
https://youtu.be/aohP_Ed1BeM

24. Rammstein - Germany - Industrial metal, Neue Deutsche Härte
https://youtu.be/-u3EJFeKYc0

23. Omega Lithium - Croatia - Industrial metal, gothic metal, Neue Deutsche Härte
https://youtu.be/GRvrs8yDBbo

22. Rhapsody of Fire - Italy - Symphonic power/neoclassical metal
https://youtu.be/Ta_KhUa3O7Q

21. DragonForce - UK - Power metal
https://youtu.be/e3IWGddh3pQ

20. Nightwish - Finland - Symphonic power/gothic metal
https://youtu.be/pzWgsEcxUlk

19. Luca Turilli's Dreamquest - Italy - electro-symphonic power metal, operatic/gothic metal
https://youtu.be/6G2Xdwajevg

18. Luca Turilli - Italy - Symphonic power/neoclassical metal
https://youtu.be/izpqDWN5iVQ

17. Lady Gaga - US - Pop, dance, electronic, rock
https://youtu.be/sz7N70IU6EE

16. Metallica - US - Thrash metal, heavy metal, hard rock
https://youtu.be/ZouJhMBLnRQ

15. Serj Tankian - US - Art rock, progressive metal/rock, avant-garde, alternative rock/metal
https://youtu.be/10nb-kjiJBw

14. Alestorm - Scotland - Folk metal, power metal, pirate metal
https://youtu.be/eNKgZouS4LY

13. Halestorm - US - Hard rock
https://youtu.be/ggoswuAS5Gk

12. Five Finger Death Punch - US - Groove metal, heavy metal, alternative metal, hard rock
https://youtu.be/owbt1_slgN4

11. In This Moment - US - Metalcore, nu metal, alternative metal, heavy metal, industrial metal
https://youtu.be/e85wdLI0JBc

10. Deathstars - Sweden - Gothic metal, industrial metal
https://youtu.be/JSJRx_7VCws

9. Helloween - Germany - Power metal
https://youtu.be/dE5WfB5Cl3E

8. Kamelot - US - Progressive/symphonic power metal
https://youtu.be/Tjh0HEe22ys

7. Iron Maiden - UK - Heavy metal
https://youtu.be/JhBw80Y54gg

6. UneXpecT - Canada - Extreme/progressive avant-garde metal, black metal
https://youtu.be/0u2uDp9MTuc

5. Kreator - Germany - Melodic thrash metal, thrash metal, industrial metal
https://youtu.be/D_brVfuIz2c

4. Mercyful Fate - Denmark - Heavy metal
https://youtu.be/1TUIFjgvVZk

3. King Diamond - Denmark - Heavy metal
https://youtu.be/bdJKLE58FUM

2. Epica - Netherlands - Symphonic gothic metal, symphonic power metal
https://youtu.be/csYBwZPCleY

1. Into Eternity - Canada - Progressive/melodic death metal
https://youtu.be/kSK238xRfR4