Edward Kelley is my favorite. He fooled John Dee, Elizabeth I, Rudolf II of Hapsburg and many others along the way to riches (Rozmberks, for instance) lived large was given access to castles and mines. He's famous because many of those mentioned were fooled until right near the end. The ones that were found out earlier in their careers tend to no longer be infamous.

Gilles de Rais, famous for being in the 100 years war with Joan of Arc and later turning child murderer was conned several times by alchemist con men. The link is a podcast that describes some of the ways he was conned.

Kelley was much more clever in his ways and probably would have a been a great con man even in modern times.