Besides "Second Chance", the '60s Fleming version of "Jeopardy" (if for no other reason than so Weird Al fans could see what Art Fleming as host was really like), the Trebek (speaking of "Jeopardy") run of "High Rollers", and the original "Supermarket Sweep", I'd save:
The Big Showdown, since only a pilot and "The Big
Fall Down" seem to still exist.
Camouflage (the '60s version), because one circulating episode begins with a review of a retiring champion's many prizes, and I would have loved to have seen her actually play at least.
I'm surprised nobody so far has mentioned the original NBC daytime version of "The Hollywood Squares" with Peter Marshall as a wiped show they would want to go back and save. Imagine how long of a compilation video we could post on YouTube with all the funny zingers and moments from that show (particularly from center square occupant Paul Lynde).
Was the episode with the "Art Fleming would never lie" incident part of that, or was that actually among the episodes that
were saved and either GSN didn't show or I missed it when they did? I'd love to have seen that episode in its entirety. On that note, I'd also save "Storybook Squares"- both the Saturday morning series and the episode part of special themed daytime weeks.