I wonder if there is a wiki engine that uses markdown

For Roadkill, it follows the Creole standard for extensions which is well
thought out and also well documented on why they chose the tokens they did
(but they do have a mediawiki focus). I think avoiding angle brackets is a
must for me, but as long as there is a summary of each token and its pros
and cons it shouldn’t matter too much - the CommonMark implementors need to
have the biggest say.