Bubblegum is a new free pitch-editing plug-in from Your Smile Is Art, available in macOS Audio Unit and VST3 formats. It analyzes recorded audio into editable notes on a piano-roll-like display, including notes in polyphonic material.
This is a creative tool rather than an automatic audio-polish button. The reported workflow is to insert the plug-in, capture a section with Transfer, then drag individual notes to adjust pitch or timing. There are also global pitch and formant controls.
Try it on a short royalty-free guitar or vocal sample and export a before-and-after clip. The payoff could be a soundtrack experiment for a family video or a custom audio sting for one of your apps; no expensive production suite is required.