Jeroen Breebaart has released SEND (beta), a freeware VST effect plugin for Windows.
JB SEND (Spectrum Enhancing Non-linear Device) combines resonating low and high-pass filters with non-linear elements that generate even or odd harmonics.
Visit Jeroen Breebaart for more information and a link to download SEND (beta).
A few other plugins have been updated recently as well, so check the VST page to see if you have the latest version of Ferox, Barricade, Omniverb and Omnisone.