There are a few ‘missing’ shapes, two of which are the ‘sideways’ versions of the pyramid corner (this thread) and a ‘sideways’ saddle shape (the one where two opposing corners on a face are removed), there’s some other weirder ones too.
Certainly for 1.0 they won’t be added, it’s a seriously non-trivial amount of work when it comes to the texture blending across neighbouring blocks for instance.