Throughout the years, I've a number of times spotted Ellen Corby in old films that have aired on TCM (Turner Classic Movies). Her filmography begins during the 1930s, though it's usually been movies of the late 1940s or throughout the '50s, and less frequently of the '60s, that I've seen her pop up in. She typically appeared in very small supporting parts (often as just a background character), such as a maid, or someone who's part of a group, a neighbour, or something like that.

Wikipedia article: Ellen Corby