Contralogic - Flange Mayhem (Pc/Free)

From the homepage:
It’s a random stereo flanging VST effect. The randomization is tempo-synced: delay and feedback parameters are selected independently for the left and right channels at intervals ranging from 1/64 of a beat to four bars.

It started life as a subtle meandering chorus effect, mainly for making mono tracks a bit more interesting.

I added a limiter because it can get fairly loud with high feedback settings.