It depends on what I'm working on; I have a set playlist that I created as soon as I started writing my novel, but I also have smaller playlists that work with specific scenes, or when writing from a particular character's POV (or for a particular mood).
Some of the songs I've been listening to the most have been:
Lindsey Stirling: Elements, Shadows, Eclipse, Take Flight, V-Pop, Heist, Night Vision, Master of Tides, Shatter Me.
Skillet: Hero, Falling Inside the Black, Comatose, Monster, Collide, Awake and Alive, Whispers in the Dark
Kamelot: The Great Pandemonium, The Haunting (Somewhere in Time), Falling Like the Fahrenheit, Sacrimony (Angel of Afterlife), March of Mephisto, My Confession, Karma, The Light I Shine On You, Moonlight, Wings of Despair, Soul Society, Lunar Sanctum, The Black Halo, Mourning Star.
Seven Kingdoms: Symphony of Stars (and my personal favourite), Flame of Olympus
Breaking Benjamin: Blow Me Away, Dance with the Devil, Evil Angel, Had Enough.
And then there's the miscellaneous stuff, like Radioactive and Demons by Imagine Dragons, The Wings of Icarus by Celldweller, Hell Arrives, Retribution, and Metamorphosis by Blue Stahli, Nightfall, Sacrificium, and Isis & Osiris by Xandria, Angels, Heart of Everything, and The Howling by Within Temptation, A Grey So Dark by Trivium, a handful of songs by Linkin Park (Burn it Down, Lost in the Echo, Castle of Glass, Papercut, The Catalyst, Points of Authority).
Yeah, I could keep going, but I'm pretty sure I'll just bore everyone, lol.