But of course, heresy, like rebellion & treason, is in the eye of the beholder. While history & orthodoxy is written by the 'winners', unless you have totally annihilated the losers, some may remainder a long time. I think that there are still some semi-Nestorian Churches in Asia but I doubt if there are many Cathars in Italy/France.
” I think that there are still some semi-Nestorian Churches in Asia...”
There are, sort of.
“... but I doubt if there are many Cathars in Italy/France.”
You’re right. But you will find Arians all through America, some even here on FR.