Alternate Python extensions (was alternate Python implementations)

[rusi]

On Aug 4, 11:15 am, Steven D'Aprano <steve
+comp.lang.pyt... at pearwood.info> wrote:
> Most people are aware, if only vaguely, of the big Four Python
> implementations:

I think the question about where Cython fits into this, raises the
need for a complementary list to Steven's.   What are the different
ways in which python can be extended/embedded. eg

1. 'Classic' extending/embedding
2. SCXX
3. PyCXX
4. Boost
5. Cython
6. Swig
7. Sip
8. ctypes

Is such a list maintained somewhere?