I say “sidekicks” for lack of a better word.
Here’s mine:
George Costanza from Seinfeld.
The only reason I ever watched that show. His dad was pretty funny too, I guess.
Jack & Karen from Will & Grace.
Schneider from One Day At A Time
Rerun from What’s Happenin’
I’m not sure that The Fonz and Urkel were that funny, but they sure stole the show.
I don’t think there’s anything in How I Met You Mother which would compel me to sit through more than a minute of it, if not for Neil Patrick Harris.
Most of them? The supporters in sitcoms are almost always more interesting than the straight-man or -woman main character. The three sidekicks in Seinfeld, for example, don’t steal the show, they are the show. Jerry is hilarious too, of course, but he often acts a lot like a representation of the audience, reacting to and wise-cracking about the antics of his friends.
Barney Fife was one of the first. Maybe Ed Norton, but I don’t think he stole the show that much. He and Ralph worked together on things, like Lucy and Ethel. Barney and Andy were going in different directions, sometimes with different plots.
One of the biggest thefts was Erkel. He was supposed to appear on just one show. Before long, it was his show.
The Bob Newhart Show. He was the main character but was also the straight man in a sea of insanity.
John Laroquette and Richard Moll on Night Court.
And Selma Diamond.
Rose (Charlie’s neighbor/stalker) is easily the best thing about Two and a Half Men, with Candy a close second. I used to think they should have their own shows, but those two are probably better in small doses.
Yeah, now that I think about it, it seems like this is the norm.
Frasier’s another one that comes to mind. Don’t get me wrong–I LOVE Kelsey Grammer, but I think David Hyde Pierce as Niles was just a bit funnier. Niles doing almost anything was gold. Niles pretending a bag of flour is a child, Niles thinking he’s high on pot, Niles pronouncing the word “fixin’s.”
I’m not positive that she counts as a sidekick, but Brittany on Glee.
I always thought Conchatta Ferrell as Berta the housekeeper was the funniest thing on that show.
There are two stock types of sitcom leads, the wacky star with the straight sidekick (think Lucy and Ethel) or the straight star with the wacky sidekicks (Andy/Barney, Newhart/Howard-Elliott-George-Larrydarrylandtheotherdarryll).
Andy Griffith said something to the effect that the straight lead and wacky sidekick tended to wear better on the audience than the reverse.
Larry and his brother Darryl and his other brother Darryl.
Here’s a list of what Wikipedia calls “breakout characters,” which is close to what you’re asking for:
Kato on The Green Hornet.
Patsy on “Absolutely Fabulous.” When David Letterman did his show in London for a fortnight, actresses Jennifer Saunders & Joanna Lunmley even built their whole guest appearance on the conceit of the sidekick stealing the show.
Berta and and Evelyn steal every scene they are in from the boys. I never cared much for Rose, but Kandi is sorely missed. And I mean sorely.
I can’t believe I forgot Evelyn! Holland Taylor is a gem, pretty much no matter what she’s in.