The Flintstones debuted on September 30, 1960 and ran until April 1, 1966, for a total of 166 episodes. That probably explains why you never saw the same episode twice in reruns when you were a kid. The show is notable for being the first animated series to run in prime-time and was intentionally created to be entertaining for kids and adults.
Before going with the Stone Age, the producers considered making the characters Ancient Romans, American Indians, Pilgrims, and hillbillies. They chose the Stone Age because it was easy to take modern conveniences like dishwashers, cars, and vacuum cleaners and convert them to a prehistoric version.
The show has been adapted into pretty much every medium, from a live-action movie, to comic books, to video games, and into different interations of cartoons, most notably Flintstone Kids, which ran for 36 episodes in 1986 and 1987.
I have two Flintstones records. One is from 1972 by Peter Pan Records and tells pretty typical Flintstones stories, the kind of crazy hijinks you’d expect on the show.
The other album is a retelling of Hansel & Gretel by the Flintstones by Columbia Records put out in 1977. This was a common album concept at this time, to take Hanna-Barbera cartoons and use them to tell old fairy tales and kids books. The Flintstones also had a Mary Poppins album, Snaggleupuss found himself in the Land of Oz, Magilla Gorilla traveled with Alice in Wonderland, etc. It was a weird concept, but kinda fun at the same time.