mine are:
full house
fresh prince of bel air
step by step
family matters
family ties
saved by the bell

I will say GAB was a difficult season 5 since the daughters grew-up and the Chief was gone.

Diff'rent Strokes

Jerry Mathers was possibly the best child actor on TV, and the early Beavers were great. Unfortunately, he had an awkward growth spurt, so the show wisely changed the focus to Wally and his more-interesting friends (Lumpy, Eddie).

Jerry Mathers was possibly the best child actor on TV, and the early Beavers were great. Unfortunately, he had an awkward growth spurt, so the show wisely changed the focus to Wally and his more-interesting friends (Lumpy, Eddie).
I agree. The later seasons were saved due mostly to Eddie, Lumpy, and Wally.

By contrast, on Father Knows Best I think when the kids were older it was a more entertaining show with more mature themes. Their final season is probably my favorite.

LEAVE IT TO BEAVER, HAPPY DAYS (although HD started its downward slide in the second season when they started doing it in front of a live audience, made Fonzie the focus of 90% of the episodes and gave the Cunninghams a different living room with no explanation.

Two and a Half Men. Even though it was Sheen's show, the older episodes when Jake was young were the funniest.

Home Improvement: The show sucked when the boys hit puberty and became grown young men. I like early seasons when they were mischevious little boys.