The first time I ever heard the word "agnostic" was from Mike Stivic on "All in The Family".

Bill..... Nye...... the science guy. Bill! Bill! Bill! Bill!

Here is another good one Temperance Brennan

Probably George Carlin and Carl Sagan...as others have said. More recently though Ricky Gervais.

Today? Brian Griffin. (The dog) Which Seth MacFarlane does in his own voice. So----Seth MacFarlane.

Meathead AKA Michael Stivic on"All in the Family."

George Carlin and penn and teller.

Addams Family? Munsters? Those are obvious. But that's what came to mind.

Brian Griffin on Family Guy, even though he’s a cartoon dog!

Michael and Gloria Stivic from All in the Family come to mind. I remember the show where Archie snuck the new Stivic baby into a church to secretly baptize him, and really pissed off atheist mom and dad.

George Carlin in the only one I can think of. Maybe Carl Sagan.

Good question, let's see. Kaine from Kung Fu my Buddhist Period, Spock I doubt he was, not sure about Captain Kirk?, Sean Leuc Picard, Carl Sagan, Einstein.Likewise Hawkeye Pierce. Mulder of course and that about takes me through to Uni years.

Mulder on the X-Files when I was in High School, is the only one I can remember seeing.

Malcolm Reynolds from Firefly

Carl Sagan

The Doctor. I loved (and still do) how often he'd (and hopefully she'd) show mystical and/or religious drivel to really be nothing more than misapprehended science.

Sorry this is off topic but your reference to Dr Gregory House reminded me of his A Bit of Fry and Laurie days and you can see he was hedging his religious bets here.......

Family Guy has a few, Sheldon from Big Bang is current but most of my tv didn’t talk religion so you only knew if a character WAS not if they were not.

Doctor Who as he was always annoyed with anyone with ridiculous religious delusions, most of the original Star Trek crew (I was deinitely disappointed in Ohura when she got all sappy at the end of the episode Bread and Circuses), Carl Kolchak the Nightstalker didn't seem to be a believer but did go in for the ritual superstition connecting religion and monsters. Rod Serling seemed to be beyond religion as host of The Twilight Zone.
My all time favourite Star Trek atheist would have to be 7 of 9, even though she did believe in the Borg collective.

On this side of the pond it isn't quite the same issue but I suppose Dave Allen was obviously questioning/ridiculing the whole religious thing especially given his Catholic upbringing.

Samantha from" Bewitched " Christians burned witches, so I'm sure she was not a fan of organised religion.

Growing up on a lake in Michigan, I didn't watch much TV. Too busy swimming, sailing, ice skating, playing flute and reading, my passion.

I remember laughing with my father at "Fractured Fairy Tales." Dad thought it was hilarious. So did I. As a family, we enjoyed the wonderful, wacky, "The Carol Burnett Show."

As a professional jazz trumpet player, Dad loved the goofy, wild band on "Sesame Street."

Uninterested in television, I never bought a TV nor paid for cable. Over the years, two people got me a TV, believing I was culturally deprived. I just use it for Netflix movies.

To watch Masterpiece Theatre shows like the beloved "Downton Abbey" and "Call the Midwife," I join an elderly friend at her house on Sunday evenings.

I remember having to be sneaky in order to catch a couple episodes of Carl Sagan's Cosmos when I was little because I wasn't allowed to watch it. It had anti-religious undertones. I didn't actually get the opportunity to watch the whole thing until I was an adult, moved out, & bought the series.

The robot on Lost in Space, The Jetson's etc. Many shows that didn't reference were open to suspicion. lol.