Atomsplitter Audio has released Flang-3R, a free 6-band stereo flanger VST effect plug-in for Windows.

Flang-3R provides control over the modulation with the standard osc shapes and Sample-and-Hold. There's feedback which brings out the sound plus dampening and mix if you want just a slight effect and shift to adjust the tone. There are 3 different modes for the speed controls and you can sync the modulation, use linked control amounts or adjust the left and right separately.