There certainly isn't as much deleted material from the third season.
As
@BillJ said, a lot of the dailies and workprint film was cut into individual frames at Lincoln and sold to the fans. For whatever reason, a lot of the third season film ended up under the knife... er, scissors.
As a side rumination, I had wondered for years why there were almost no frames available for some deleted scenes, e.g, the Peter Kirk scene from Op--An and the McCoy getting phasered scene in Space Seed. The Roddenberry Vault Blu-ray set was very illuminating and explained the reason for this observation. That is, their film source was the same as that used by Lincoln and, thus, not all of the dailies and workprint film had been cut up (or discarded). It was interesting for me to note that I have frames from deleted scenes that are not on the Roddenberry Vault set and they have rolls from deleted scenes that I've never seen frames from.
Of course, there are the "missing" rolls, i.e, rolls of film that Roddenberry gave to fan clubs (with the intent of being cut up) and those that found their way out of Lincoln. I have examples of the former and have seen examples of the latter. I'm always on the hunt for these rolls because, potentially, they may show material from the great undiscovered country! Some certainly do...
