Intense, constant ringing drone
Glassy nightmare drone with vocal accents
Seething bubbling swamp with building canary-like, repeating notes
Drone - plucked guitar string, hi-pitched oscillating mosquito whine with swelling, multi-timbral string ...
Deep purring rumbling monster drone
Sound design accent: low-pitched, resonant, reverberating, explosion
Dark descending drone with reverberant hollow background noises
Sound design accent: processed string notes