Spin offs have been around since the fifties, thing is they are rarely any good, the original idea doesn't expand enough. However they continue to be made. Perhaps the greatest of all spin offs is Frasier. Excellent and eminently watchable, it took the intellectual approach and made a show as great if not better than the show from which it came; Cheers.
Here a selection of spin offs for your delectation with the progenitor named.
the Flintstones kids-The Flintstones (Also spawned Pebbles and Bam Bam)
George & Mildred-Man about the House (Also spawned Robin's nest)