Touch of malice has to be up there. The Hive God’s were able to cleave planets apart with their swords. Oryx’s heart represents the combined power of the billions of tithes he had received, and also both of his sisters, his former god one of the worms and likely a lot more stuff. Oryx had likely consumed a reasonable portion of existence, likely passing over 10-20%. 20% of the universe concentrated in a single energy ball powering a gun? Yeah, you can’t really beat that for theoretical power. Edit: oh and it’s a weapon of sorrow, one of the very short list of things that can cause true death for Guardians.