About the Free Synth plugins (VST/AU) category

Here short demos and links to free VST’s.
So only free stuff here!

Absolute top of my list would be Full Bucket Music’s many free synths (and some FX).

http://music.fullbucket.de/vst.html

The only synth/FX not shown in the image below is the “qyooo” (a complex modulation synth).