Excuse me for choosing mainly British character actresses, but that’s the way it is. A top 10 list would look something like this:

Rachel Roberts
Katharine Hepburn
Joan Greenwood
Julie Christie
Margaret Rutherford
Joan Hickson
Mona Washbourne
Una O’Connor
Lillian Gish
Brigitte Mira

With mentions also to Maggie Smith, Katie Johnson, Coral Browne, Tilda Swinton, Alison Steadman, Ann Way, Helen Mirren and Emily Watson.