Distortionator mk2: A simplistic distortion plugin, with two modes. The first mode is a modified threshold-type distortion (although the modification isn't particularly noticeable, sound-wise). The second mode is called Sine Wave distortion, although it's actually closer to frequency-modulation, as the audio input is used as the index to a sin() function.
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Soul Force!: A fairly standard waveshaping distortion plugin, made more interesting through the use of feedback to control the shaping. Can get pretty loud and obnoxious. The GUI was done in Blender, and you can find the .blend file in the source code zip.