How many Jedi survived Order 66? Was Master Yoda the only one or are there any more who disappeared into the shadows?
Various semi-canonical sources (novels, etc) indicate that
- some Jedi survived the purges
- Not all force users were Jedi nor Sith
- Not all Jedi were targeted
We see Mara Jade and at least one other dark apprentice in the novels, plus at least two non-Jedi, non-Sith force users in the Heir to the Empire trilogy.
It's probably safe to say that Obi Wan and Yoda are the last of the Council's Jedi Masters; various failed apprentices and former Jedi seem to be out there as well, EG Count Duku. (Dark Empires, Eps II & III) Rebels shows us a couple other Jedi Knights also survived.
Plus, there are implications that there were other Jedi temples with training centers, and that not all might have been found.