Another one that comes to mind, wasn't the finale for the show but for the long time host.
During the first episode I believe of the 1977-78 syndicated season, Garry Moore came back as a guest host to announce his retirement due to health issues that he was going through. Joe Garagiola was named the new host. If it was due to this change or due to other reasons, this would prove to be the final season of this classic series on American television until 1990.
Bill Cullen served as host during the previous season during certain episodes when Garry Moore was ill. The show decided that the panel's cast was lacking without having Bill as one of the panel, so the powers that be decided to name Joe permanent host.
I am grateful that Mr. Moore went on to live until almost the end of 1993, so he had 16 years of retirement to enjoy. It was a cozy set and a cozy show to me, one of the very first game shows I remember my parents watching when I was so very young, circa 1970/71...I also remember What's My Line? and Pay Cards! Those were my first memories of game shows and my obsession with playing cards began back then. When Gambit came out I about melted into my socks seeing those giant cards, and did so again with the Perry, Eubanks & Rafferty versions of Card Sharks.