Joerg Knieschewski released SimpleStereoWidening, an AUv3 for quickly adding some width to your tracks. The app appears to be genuinely free, without any IAPs.
SimpleStereoWidening App Store Description:This AUv3 Audio Unit is an easy to use stereo widening plugin to adjust the stereo image! You can add width and depth to your music without altering the sound! This plugin features an analog like correlation meter inspired by old analog studio console circuits from the golden age of analog recording!
I try to encourage developers to make videos for their apps, so I'm hesitant to criticize them when they do it poorly. Doubly so for a free app. This example is inexcusably poor though. He does the video on his phone in the wrong orientation, and even acknowledges that since he's using the audio from the iOS screen recorder it is in mono. Making it both sideways, and useless as a demonstration of a stereo effect app. I'm truly amazed.