I also found on METV Toons The Pebbles And Bamm-Bamm Family Hour and from what I saw of it from the intro this cartoon was a spin-off of The Flintstones with Pebbles grown-up and Bamm-Bamm all grown up as the leaders of a The Partridge Family-like band. How did the idea for this show come about? Because I had never seen it before and was it another underrated Hanna-Barbera cartoon when it first came out?

I also found on METV Toons The Pebbles And Bamm-Bamm Family Hour and from what I saw of it from the intro this cartoon was a spin-off of The Flintstones with Pebbles grown-up and Bamm-Bamm all grown up as the leaders of a The Partridge Family-like band. How did the idea for this show come about? Because I had never seen it before and was it another underrated Hanna-Barbera cartoon when it first came out?

It was very underrated and it wasn't bad.

The show had 16 episodes in 1971-72, and the lead voices were Sally Struthers and Jay North.

The episodes were rerun, along with a few new episodes, in the Flintstones Comedy Hour the following season. The next season was retitled the Flintstone Comedy Show, and the Pebbles/Bamm Bamm segments were dropped.