We all know the story about how little of the 1960s episodes of the "Tonight Show" were saved, but a few are popping up. First off the infamous Tiny Tim wedding episode, the highest rated episode the show had before Johnny's final episode. (Skip to the 63rd minute to see the ceremony).
Second a New Year's Eve 1965 episode. As the episode description indicates, it's been floating around Internet Archive for a while. You even get to see the 15 minutes EdMcMahon did without Johnny (apparently those 15 minutes weren't seen in many markets so Johnny just skipped them)