Bojo Software makes some freeware VST plugins for Windows
Synth. Simple, easy to use interface - 16 voice polyphony - 1, 2 or 4 oscillators in each voice - True stereo mode - Two volume envelopes - 5 different oscillator...
Virtual organ. Organ One is a 16 voice virtual organ for the PC VST platform. Simple to use, but capable of producing a large variety of high quality organ-sounds.