Here are some Free VST plugins, that you can use with any vst supported software. Enjoy!
Virtual Analog Synthesizer Module v1.01
Monophonic analog synthesizer
Like futura it uses physical modeling to emulate analog wave forms. but a LOT better
12 voices polyphonic, Full MDI learn implementation, Envelope & LFO Host syncable, Sync and FM
Lektro VSTI is a Phase Distortion Synthesizer with a lot of modulation capabilities.
16 voices polyphonic, substractive / FM 2 operators synth, MIDI learn implementation, Comfortable XY Pad, Auto Pan
Substance is a virtual analog software synthesizer (VSTi) emphasizing simplicity, flexibility, and sound quality. The key factors in the design of Substance were that it should sound great, without effects, and that it should all fit on one page.