I know Tsonga is one of them and he leads 5-4, but who else? surely after this year Nadal is out of the question? and what about Fed now? the only other player i can think of who might also have a winning record against Nole is Murray but i'm not sure.
There are 12 players that have winning record against Djokovic:
O. Rochus 3:2
Safin (Retired) 2:0
Dan Scheppingen scratch: Retired) 1:0