I came across some nice Markdown extensions.....
https://facelessuser.github.io/pymdown-extensions/
Especially, I like the B64 (if one wants to email images), caret, details (and emoji 
)
Would it be possible to add the extensions from https://pypi.python.org/pypi/pymdown-extensions
to Plone / Markdown ?
If yes, … how should it be done ?