(Cakewalk synths) some are by Roland. Great for mixed Dubstep and EDM
Cakewalk - Virtual Instruments
(Sylenth1) sounds like a Virus and is great for Trance and House and EDM
Sylenth1 | LennarDigital
(Synthmaster) is cumbersome to work with and classy, great for Electro and EDM
SynthMaster 2.6: Award Winning VST/AU/AAX/RTAS Software Synthesizer.
(Vacuum Pro) One I haven't tried but their demo is geared towards medium to harder EDM like hard EDM and even could be used for something like Industrial. Think I'll give that a shot sometime.
(Waves) Effects, Mastering, and Synth and realistic guitar. Industry's best IMO.
Audio Plugins for Mixing, Mastering & Recording | Waves
(Sonalksis) professional Effects
WEBSITE for VST's
KVR: VST Plugins, Audio Units (AU Plugins) & AAX Audio Plugin News, Reviews and Community - plus iOS (iPhone and iPad) and Android Audio App News Too (Virtual Instruments & Virtual Effects)