So who are some celebrities you would think a lot of people would go “Hey! It’s that guy/girl!” in a show or movie, but whom they probably couldn’t name?
Obviously this is a relative term, subject to opinion…but here’s some people who spring to mind immediately.
Who would be your candidates for the best to suit this category? I’m sure there must be thousands.
Frank Nelson Frank Nelson torments Jack Benny - YouTube
Simon Oakland (I had to look him up just yesterday) The Night Stalker Part 1of 8 - YouTube
Wouldn’t many character actors fit in this category (assuming they have been in enough movies)?
Hey look, it’s That Guy! From here, James Rebhorn is my ultimate “That Guy” although I certainly know who he is. There are some other guys who you might confuse him with as well.
In the OP I recognize Guzman by name and face. I always forget Grant’s name but know who she is; she is pretty much “busybody bitch” in everything. Don’t know the other two.
Michael O’Keefe. He usually plays smart, sarcastic and often working-class Irish-American guys. 2 pieces of trivia: a. he played six different characters on* Law & Order* series; and b. he was the kid from Caddyshack.
I’m at a loss how to answer. I don’t know their damn names!!!
Wasn’t he also on Roseanne for awhile?
And that movie where Robert Duvall was an asshole Marine pilot?
Nearly anyone in the cast of Rene Clair’s 1945 adaptation of Agatha Christie’s AND THEN THERE WERE NONE. Barry Fitzgerald, Walter Huston, Roland Young, Mischa Auer, [C. Aubrey Smith, Judith Anderson, etc.
In more recent films, I love the weird guys:
Timothy Carey Timothy Carey - IMDb
Vincent Schiavelli Vincent Schiavelli - IMDb
And was married to Bonnie Raitt (can’t remember if they are still together…)
Thanks for the link! We always talk about “That Guy.” It can mean either interesting character actor OR one that vaguely resembles another (usu. more famous) actor. Think Nick Nolte/Gary Busey back in the day.
As someone else said, I can’t really answer this question because I don’t know their names. Even after I look them up on IMDB, I promptly forget.
After I attempt to look them up on IMDB, if I’m still not 100% sure which guy I’ve located, then I cross-reference with the Law and Order or X-Files episode they’ve been in. 
Edit: Oooh, I got one. Sydney Lassick: Sydney Lassick - IMDb
Valérie Quennessen
You may not remember the name, but if you were an adolescent male in the 1980s, you certainly remember the . . . face.
She was the French chick in French Postcards.
She was the French chick in Summer Lovers.
She was the princess in Conan the Barbarian.
HBO made a fortune from her.
Died in a car crash in 1989, age 31. 
This may not be the right crowd to not get his name, but I think most people out there in the real world would have trouble naming Eric Roberts, although he has been in, I think, literally everything.
A few people who’ve been in everything (but whose names still go unrecognized).
John McGiver
http://en.wikipedia.org/wiki/File:John_McGiver.jpg
Kenneth McMillan
Arthur O’Connell
Robert Prosky
John Randolph (Oh yeah, that guy was the Grandpa in*** Christmas Vacation***!")
This guy appears in every Jerry Bruckheimer movie I know! But I never remember his name…
(It’s William Fichtner)
For years, whenever there was a TV role for an old lady, one of the following actresses was almost sure to get it:
Nedra Volz: Nedra Volz - IMDb
Loretta Tupper: Loretta Tupper | Muppet Wiki | Fandom
And the go-to old man was Burt Mustin:
