I know many. But I will start by saying Mr. Belvedere had three kids on the show.

My Three Sons (Until Dodie came along)

Diff'rent Strokes (until later on)
Gimme A Break (until later on)
Family Ties (until they added Andy)
Growing Pains (until they added Chrissy)
The Hogan Family
Full House
Family Matters (until Judy went upstairs)
Roseanne (until they added Jerry)
Unhappily...Ever After
8 Simple Rules

Good Times

Grounded for Life - Lily, Jimmy and Henry (though he vanished in the final season).

Step by Step - JT, Dana, Karen, Al, Mark, Brendan. Count them, there's three in there. As well as three more. :)

Obviously, me listing SBS was a joke. Please don't attack "The Adamizer." :)

The Nanny (until the finale)

Happy Days

...until Chuck was disintegrated.

Everybody Loves Raymond
Home Improvement

Reba, until Cheyanne got married after she got pregnant, LOL.
Still Standing
Patty Duke Show if you count cousin Cathy who lives with the Lanes.

(until Judy went upstairs)


...until Chuck was disintegrated.

:lol:

my wife and kids

And Drake & Josh

The Simpsons, although some might argue that Homer is the 4th child ;)

Petticoat Junction...three adult daughters, anyway :)

Full House and Home Improvement.

blossom

Boy meet world. they had eric the older brother, morgan younger sister and then cory.
The Wonder Years- Wayne, Karen , AND kEVIN
Family Matters- EDDY, LARUR, AND JUDY.