Need Recommendations for Playlist
Here are some tracks I can think of that can be good for your Guardians playlist:
Accept - "Metal Heart" from Metal Heart
Avenged Sevenfold - "Nightmare" from Nightmare
Volbeat - "Still Counting" from Guitar Gangsters & Cadillac Blood
Queensryche - "Neue Regel" from Rage of Order
Battle Beast - "Last Goodbye" from Last Goodbye
Enforcer - "Mask of Red Death" from From Beyond
Crimson Glory - "Masque of the Red Death" from Transcendence
Bruce Dickinson - "Afterglow of Ragnarok" from The Mandrake Project
3 Inches of Blood - "Silent Killer" from Here Waits Thy Doom
Also if any of the tracks above encourage you to check out more of those bands and come up with some ideas for the monthly Spotify playlists, here's a thread to add in your playlist suggestions: https://metal.academy/forum/9/thread/479