We're getting down to it now. None of these next names should come as a surprise to anybody.
The "wizard beard" is one of the best-known stereotypes in the bearded world. Sure, Gandalf had one. Dumbledore had one too. Any decent wizard has to these days. But the roots go back to Merlin, the most famous wizard in the history of the world, the origin of the entire wizard look, and the wearer of one seriously magical beard.