Here is a shape key animation test with bounce keyframe interpolation.
The bounce interpolation can be activated for all kind of animation keyframes by pressing T-key into the Graph Editor.
And there are some other interesting modes for keyframe interpolation.
Animation and 3d-preview on Sketchfab.
Demo-Video: https://www.youtube.com/watch?v=ZwyjKF1Vgfw
Amazing!!great work