Michael J. Pollard, who was in “Bonnie and Clyde” and “Roxanne”, among others.
James Tolkan (Principal/Marshal Strickland in the Back to the Future trilogy) was seemingly everywhere in the Eighties & Nineties.
And the Star Trek episode “Miri” – “Bonk bonk on the head!”
One of those guys whose face never really changed. 
When you have a small part for a non-threatening old woman, you call Frances Bay. One of those actors who’s been “old” seemingly for forever.
He’s an okay actor in my book, but a fantastic narrator. Flawless delivery and word pauses without dramatic emphasis. Just watch American Experience and hear for yourself. Perfect.
Yes, Anton Lesser is “everywhere”. He also has a distinctive voice.
I’ve thought of some others to mention. Bonnie Bartlett https://www.imdb.com/name/nm0058783/?ref_=nm_ov_bio_lk4 and William Daniels https://www.imdb.com/name/nm0200122/?ref_=nmbio_bio_nm.
Both recognisable faces with long TV resumes. They have been married in real life since the 1950s and both still working. Most recently, I saw William in Grey’s Anatomy, he had a recurring role in that.
Since he’s been dead for going on 50 years, the odds are not so good that Sonny Tufts - IMDb Sonny Tufts gets his name used “in jest” as much as he did say 20 years ago. But there for a while you’d hear other showbiz types use his name almost as a running gag on TV talk shows and the like.
If I ever saw him in a movie, I can’t recall where, but the name has stuck!
And his female counterpart would have to be Zasu Pitts - IMDb Zasu Pitts.
They were almost the Randolph Scott (Blazing Saddles) counterparts 20-30 years ago.
Zasu (pronounced SAY-zu, BTW) Pitts was one of Hollywood’s best character actresses. She could upstage W.C. Fields.
He’s gone now, but Pete Postlethwait (Mr. Kobiashu in The Usual Suspects) was everywhere.
A busy annoying biddy. She has 220 credits, ten this year alone.
I mentioned James Karen in another thread recently. Known as Mr. Pathmark to supermarket shoppers in the Northeast, he’s 94 and still working occasionally. He’s another one with 200+ credits.
All this way and no mention of the incredible Burt Mustin?
You needed an old guy in the 50s through the 70s Burt was your guy. He started acting seriously at 67(!!!) in 1951 and his last appearance was in 1976. Appeared on innumerable Jack Webb shows - Dragnet, Emergency, Adam-12 - as well as The Brady Bunch (playing a guy who’s dad was killed by Jesse James!) and All in the Family.
Just a classic ‘that guy’ actor.
He is probably best known as Mr. Pathmark but I will never forget him in Return of the Living Dead-- an underrated zombie movie along with Night of the Comet. Night of The Comet featured That Guy Geoffrey Lewis.
Yes! And I remember being taken out the movie momentarily when Mr. Pathmark showed up. It was like Mr. Whipple showing up with some Charmin.