RealSpread

Truality Audio has released RealSpread, a free VST plugin that widens a sound source.

RealSpread "Stereoizes" a mono audio signal or widens a stereo one, without practically compromising mono compatibility. The spartan GUI conforms to RealSpread's philosophy of simplicity in plugin design.

RealSpread is more effective on single sources, for example a single (mono) Drums Overhead or Room microphone. Of course, you can experiment with stereo sources.

https://trualityaudio.weebly.com/free-vst-plugins.html