At this point very few &#x27;actually used&#x27; (meaning, used by more than a handful of organizations at most) are Py2 only.  There are a few still in the process of porting, and a few that will never be ported due to being replaced (but are still somewhat popular for one reason or another.)<p>For those who don&#x27;t know: <a href="http:&#x2F;&#x2F;python3wos.appspot.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;python3wos.appspot.com&#x2F;</a>