1. My biggest "go to's" for dark sounds and exploration would probably be Dark Matter and Monolith instruments for Kontakt, both from String Audio. I really enjoy their engines, the ability to easily add your own samples, and just hitting random and finding cool sounds...
2. FabFilter L2, MB, and Q3, A.O.M. Invisible Limiter G2, TDR's Limiter 6 GE, PSP Xenon, Newfangled Audio Elevate, Kush Audio SILIKA, Tone Projects Unisum, SIR Audio Standard Clip Pro, pretty much all the Valhalla line-up, Audio Ease Altiverb, Klanghelm VUMTdeluxe, quite a few from Acustica Audio, top faves being Ivory, Taupe, Coral, Scarlet, Diamond, and Cream, Softube DS-1 MK3 (and I just got the soft version of the Chandler Curve Bender, really remarkable, and way more portable than my hardware one
), oeksound Soothe 2, and u-he's Satin all get time in my mix and mastering chains... there's more (there's always more, right?!) but those are the major players in my world at present.
