This is a paid asset, but now you can download Soft-Body Objects for FREE, but please remember this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
Soft-Body Objects v1.0
“Soft-Body Objects” is a package that contains low-poly ready to use soft-body objects. Soft-Body physics are totally different than Unity’s built-in physics engine. So this package uses “Bullet Physics” to achieve soft-body.
“Soft-Body Objects” is;
+Full VR compatible (SteamVR, Oculus, etc.)
+15+ different objects that prepared for soft-body physics