I just mentioned Moonstruck (1987) in a comment, and that got me thinking again. I really like that movie. A wonderful cast, a great script, and good direction. The movie works.
But it doesn't work without Bit Actors. Two that come to mind are Loretta Castorini's aunt and uncle who run a grocery store. Of course Loretta is played by Cher (b. 1946). Julie Bovasso plays Rita Cappomaggi, and Louis Guss plays Raymond Cappomaggi.
Julie Bovasso (1930 - 1991) only has 29 title on IMDb, released from 1958 to 1992. She spent most of her career on the stage and doing other work, such as writing. She was also the dialog coach on Moonstruck, which was more important than you would think. She was able to blend the Italian and New York accents into something truly believable. Bovasso also did this for Prizzi's Honor (1985).
Perhaps her most famous role was as John Travolta's (b. 1954) mother in Saturday Night Fever (1977). A few other movies she was in are The Verdict (1982) with Paul Newman, and Betsy's Wedding (1990) with Alan Alda (b. 1936).
Louis Guss (1918 - 2008) has 102 titles starting in 1957. Born in New York, his accent came easy. He did a lot of TV throughout his career. We see him in The Godfather (1972), and he is in The Laughing Policeman (1973) which was a strange movie starring Walter Matthau (1920 - 2000) as a cop. Matthau should never be cast as a cop.
Here are some of his better titles -
Harry and Tonto (1974)
Fun with Dick and Jane and New York, New York in 1977
Used People (1992)
The Cemetery Club (1993)
But he also made movies like -
A Tale of Two Pizzas (2003)
The fact is that he didn't do much on the large screen, but what he did was good. I only counted 31 movies, the rest was television work, but I think Bovasso had better titles.
Moonstruck has many Bit Actors in the mix. Think of the waiters in the little Italian restaurant, and the bakery girls. Add them up and you have a great way to spend an evening. Champagne cocktails, anyone?