Where did all of the con artists go?

There was also the El-Aurian from DS9 "Rivals" who used his powers of empathy and suggestion to con people. And the Wadi from "Move Along Home" who made Quark think Sisko, Kira, Dax, and Bashir were in danger when they never were (though it was only because Quark conned them first).

 

Maybe the Terran Empire is onto something.

 

And also the two beautiful women in "Two Days and Two Nights"
who really was two nasty Alien dudes, that conned Malcolm and Trip on Risa...