Waveshaper/wavefolder plugins don’t get much simpler than Audec’s Shape, a new VST/AU plugin that you can download for free.
The top section of the interface is taken up by the Scope, which visualises the shaping curve. There are five to choose from: Hard Clip, Soft Clip, Tube, Triangle, and Sine.
What few controls there are are positioned below this. The Input knob adjusts the amount of gain - more gain produces more harmonics - while dialling in the bias creates asymmetrical distortion, which leads to “warm even harmonics”.
Over to the right you’ll find Dry/Wet and Output controls, while you also have the option to select the oversampling factor (increasing it means less noise but more CPU overhead and latency).
You can download Shape for free from the Audec website. It runs on PC and Mac in VST/AU formats.