I have been watching a lot of pre-code/30s/40s/50s films and made the following observations - obviously Hollywood favours a few certain looks so this isn’t surprising, and also these are just visual comparisons, no reflection on anyone’s acting.
1: Carole Lombard/Amber Valletta

2: Katharine Hepburn/Parker Posey

3: Anne Baxter/Florence Pugh

4: Bette Davis/Amanda Seyfried

5: Lena Horne/Antonique Smith

6: Joan Crawford/Natasha McElhone

7: Billie Burke/Patricia Clarkson (I can see someone else in her face but cannot put my finger on it!)

8: Una Merkel/Zoë Wanamaker

9: Ann Dvorak/Troian Bellisario

10: Joan Blondell is giving me young Carol Kane and just a little young Emma Thompson too

11: Ruby Keeler/Casey Wilson

12: the underrated Ida Lupino gives me Anya Taylor-Joy and just a little Allison Janney

13: Judy Garland/Debi Mazar

14: As she got older Loretta Young became very Allison Janney, but in the 1930s she was more Maggie Gyllenhaal

15: Theresa Harris/Sonja Sohn (Harris was woefully uncredited and under-utilised throughout her career but she is wonderful in 1933's Hold Your Man alongside Jean Harlow as a character with agency and story, though once again - no credit)

16: Dorothy Mackaill/Lea Seydoux (what wouldn't I give for lost silent film The Crystal Cup, where the suit picture comes from!)

17: I've watched SO many Jean Harlow films, and her particular quality - engrossing, transformational between photos and the screen, yet tangibly human - doesn't translate to just anyone. The closest example I can think of with that vibe currently would be Elizabeth Moss.

18: Myrna Loy/Lorde (it took me a minute - I was like, is she a young Miranda Otto? Mary Steenburgen? But then it clicked and now this is all I can see)

I wanna circle back to Carole Lombard, something about her feels so late 90s/early 2000s - from her comic sensibility to her jawline. Put it this way, if there’s any pre-code actress I could picture wearing a dress over jeans on the red carpet in 2001, it’s Lombard.

19: Nina Mae McKinney/Ruth Negga with a little Kerry Washington

20: Marie Dressler/Peg Phillips, both best-known in their sixties

21: Luise Rainer gives me a little young Meryl Streep with some definite Bebe Neuwirth

22: By this point in the thread you might look at Virginia Bruce and say "isn't that just every symmetrical blonde actress" and, sure, but specifically I see the great Jean Smart in her performances.

24: Greta Garbo is hard to pin down but - not just visually but in terms of that ineffable quality - I think Laura Benanti gets the closest.

25: Norma Shearer gives me 100% Stephanie J Block

26: It may be the fact that they both played Elizabeth Bennet but I do see some Jennifer Ehle in Greer Garson's face!

27: Marsha Hunt (the other one) is pure late 90s Larisa Oleynik

28: Edna May Oliver/Jackie Hoffman

29: Maureen O’Sullivan/Joanna Going

30: Veronica Lake and Traci Lords

31: Mary Astor and Louisa Harland

32: Eve Arden and Addams Family Joan Cusack

33: now, Rosalind Russell and Lena Headey don’t look overly alike, but both of them have those eyebrows which know something you don’t know!

if anyone is interested, I'm writing a list of recommendations/mini reviews based on the films I've watched which inspired this thread. Also if no one is interested, I'll still write it. As you can probably tell by this thread.