This should be an honorary "Big Five" Oscar winner
The "Big Five" Oscars are Picture, Director, Actor, Actress, and Screenplay (either original or adapted).
Only three films have won in all five categories: It Happened One Night, One Flew Over the Cuckoo's Nest, and The Silence of the Lambs. Several more have been nominated in all categories: https://en.wikipedia.org/wiki/List_of_Big_Five_Academy_Award_winners_and_nominees
I submit that Kramer vs. Kramer should count as an "honorary" member of the Big Five list. It won Picture, Director, Screenplay (adapted), Actor, and Supporting Actress. Meryl's performance was good enough and big enough to have been a Best (Lead) Actress role (nowadays I wouldn't be surprised if she would have received a lead actress nomination for that role).