I am trying to make objects fall onto a plane and actually pile up like normal objects would.
Instead of that, the objects fall, bounce around a few times, and end up merging with each other until they're all totally flat on the plane:
I've tried many different settings in Physics for both the plane and the cube, I've even tried to play with Molecular add-on but I couldn't find what settings relate to "Particle Self-Collision" in Blender and/or Molecular.
Being able to create a pile of objects that looks realistic (as if objects were dumped on the ground from a container) as such (bills only, not the coins):
Note: There are some similar threads around but the website "blenderartists" seems to be down as I write this.