It's a derivative question of "What are the only 3D objects with which it is possible to fullfill a volume?" and so the question only concerns these objects.
I feel cube and the object built with pentagon are some of them (if there are any others in regular polyhedra).
But answers can also consider what suggested Parcly, ie "There is a volume filling construction using a mix of regular tetrahedra and regular octahedra."
Kind Regards
