SynthGeek has introduced SG-Freakshift, a free Windows audio effect they describe as "a not-quite-technically-correct stereo frequency shifter".
According to SynthGeek, the effect only strives for true frequency shifting in a certain range of frequencies, in order to minimize CPU usage. Frequencies outside this range get an effect closer to ring modulation.
There is also a simple distortion effect and LFOs for modulation.
This crazy oscillator now has even more features