i found this by accident... thot it was kinda interesting.
There are quite a few TV shows whose copyrights were never renewed or
were renewed improperly and have fallen into the public domain. There is
an ongoing effort to determine what is & isn't protected but the list is
far from complete.
I've appended a partial list of, arguably, the most popular shows & the
number of public domain episodes of each that have been discovered. Bear
in mind however that these are not necessarily consecutive episodes or
even from the same season.
In some cases "special" episodes (anniversaries, births, deaths, etc)
were properly copyrighted with an eye towards future rebroadcasts.
Adventures of Jim Bowie 14 episodes Scott Brady
Adventures of Ozzie & Harriet 104 half-hour, b&w shows.
Adventures of Robin Hood 80 half-hour b&w shows Richard Green as Robin.
Adventures of Sherlock Holmes 39 half-hour b&w shows Ronald Howard as
Holmes.
Adventures of Sir Lancelot 30 episodes, some in color.
Annie Oakley 24 shows Gail Davis
Beverly Hillbillies 52 half-hour shows.
Bob Cummings Show 20 Shows of "Love That Bob."
Bonanza 31 One-hour color shows
Buccaneers 28 episodes
Cisco Kid -- 32 Color episodes. Duncan Renaldo.
Dragnet 24 half-hour shows
Dusty's Trail 17 color shows with Bob Denver.
Flash Gordon 8 half-hours Steve Holland as Flash.
Frontier Doctor 12 shows with Rex Allen.
George Burns & Gracie Allen Show 13 episodes.
Hawkeye & Last of the Mohicans 13 shows. John Hart.
I Married Joan 24 half hours with Joan Davis, Jim Backus.
Lancelot Link: Super Chimp 3 discs with 24 short adventures. Color,
live-action chimps
Lawless Years 24 shows. Great crime show set in 1920s.
The Lone Ranger 16 half-hour b&w shows + 1 color.
The Loretta Young Show 30 half-hours with Loretta
The Lucy Show 30 half-hour color shows with Lucille Ball.
Man with a Camera 29 episodes with Charles Bronson.
Mr. & Mrs. North 32 episodes. Richard Denning and Barbara Britton.
My Little Margie 24 half-hours with Gale Storm, Charles Farrell.
One Step Beyond 56 half-hour shows about the weird.
Petticoat Junction 20 Shows.
Private Secretary 16 shows with Anne Sothern.
Racket Squad 20 shows. 1950's bunco squad Reed Hadley.
Ramar of the Jungle 24 episodes with Jon Hall
Range Rider 20 shows. Jock Mahoney, Dick Jones.
Red Skelton Show 20 half-hour shows.
Rocky Jones, Space Ranger 6 features made up of 3 TV episodes each.
Roy Rogers Show 56 half-hour black and white shows.
Sergeant Preston of the Yukon 12 color PD episodes.
Stories of Century Western series with famous outlaws 36 shows.
Trouble with Father 20 episodes with Stu Irwin.
The Veil Boris Karloff supernatural show. 10 episodes.
Victory at Sea 26 half-hour World War-II documentaries.
http://www.answers.com/Q/What_tv_show_is_are_in_the_public_domain